Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials
«Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials» is an annual, i.e. it publishes scientific papers on both basic and applied problems of modern nanoscience. The journal «Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials» is regularly published at the end of each calendar year since 2009. On the one hand, the annual is interdisciplinary. On the other hand, it publishes papers corresponding to one rapidly developing brunch of modern science, i.e. to the physicochemical aspects of nanotechnology. As conceived by the editorial board, the mission of the journal is to disseminate new scientific results obtained during the last year, to summarize them and to contribute thereby to formation of prospects for the further development of this scientific direction. First of all, physical and chemical aspects of nanoscience are meant and its applications in nanotechnology. At the same time, discussions of nanotechnological aspects of environment science, biology and medicine are also welcomed. Another specific feature of our annual journal is succession to physics of surfaces and colloid chemistry. So, our journal accepts original papers with presentations of new results on surface phenomena, nanoscience and nanotechnology. The quality of papers and significance of their results will be evaluated by the members of editorial board and independent external reviewers. The Journal «Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials» also publishes short notes of 5 pages or less (including figures, tables). Letters to the Editor commenting articles already published in this Journal will also be considered. Review articles providing an analysis of particular fields are also encouraged. The degree of originality of the articles, their level and the significance of the presented results will be assessed in the process of double-blind review by members of the editorial board and external independent reviewers of the journal.
ISSN (print): 2226-4442, ISSN (online): 2658-4360
Media registration certificate: ПИ № ФС 77 - 47789 от 13.12.2011
Founder: Tver State University
Editor-in-Chief: Samsonov V.M.
Frequency / Assess: 1 issue per year / Open
Included in: White list (3rd level), Higher Attestation Commission list, Web of Science, RISC, CAS
Current Issue
No 17 (2025)
Articles
Study of electrophysical properties of pure and intercalated highly oriented pyrolytic graphite
Abstract
Graphite intercalated compounds have attracted significant attention from researchers due to their unique physical properties. Metals and molecules introduced into the interplanar spacing of graphite can act as donors or acceptors of electrons. This means that intercalation with different chemical elements can influence the carrier concentration in graphite. As a result, graphite intercalated compounds can exhibit different electronic, thermal and magnetic properties. In this work, the possibility of modifying the electrophysical properties of highly oriented pyrolytic graphite by intercalating it with potassium atoms is demonstrated. Intercalation of highly oriented pyrolytic graphite by potassium was performed using a two-zone method. The intercalation stage of the sample was determined from Raman spectra data. Measurements of the electrophysical properties of pure and intercalated graphite were carried out using the van der Pauw method (four-probe method). It has been shown that intercalation of highly oriented pyrolytic graphite by potassium leads to a decrease in its specific resistance and Hall constant, while there is a significant increase in the concentration and mobility of charge carriers. Considering that the change in the electrophysical properties of graphite during its intercalation occurs without the destruction of the crystalline structure, which leads to a deterioration in the physical characteristics, it can be said with confidence that this method is one of the most promising in modifying electronic, surface, and other properties of layered carbon materials.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):7-14
7-14
Yb3-xErхAl5O12 for optical thermometry: measurement of luminescence caused by transitions from non-thermal coupled levels
Abstract
Erbium-doped ytterbium aluminum garnet has been synthesized by a precursor method. The samples were characterized by Infrared spectroscopy and scanning electron microscopy. Under infrared excitation at 980 nm, the compounds exhibit intense upconversion red luminescence in the visible range. According to the concentration dependences of upconversion luminescence, the optimal concentration of erbium in Yb3-xErхAl5O12 compounds was x=0,3. The thermoluminescent characteristics for Yb2,7Er0,3Al5O12 garnet were determined by the ratio of band intensities in the visible and near-infrared ranges due to transitions from non-thermal coupled energy levels 4F9/2 and 4I9/2 of Er3+ ion. The maximum values of absolute and relative sensitivity in the temperature interval of 25-225°C have been determined. The results obtained show that it is reasonable to use the method of comparing two luminescent lines assigned to non-thermal coupled energy levels of lanthanide ions for optical thermometry and that phosphors based on Yb3-xErхAl5O12 garnet hold promise as materials for temperature sensors.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):15-25
15-25
Influence of optical anisotropy on the extremely short pulses propagation in a polymer composite with carbon nanotubes
Abstract
In this paper, we study the evolution of electromagnetic waves in an anisotropic optical medium with carbon nanotubes and polymers. The relevance of the work is due to the active use of such nanocomposites in modern nanophotonics and optoelectronics, where control of femtosecond light pulses is required. The main attention is paid to the influence of anisotropy of optical properties, which occurs due to a certain orientation of carbon nanotubes in a polymer matrix. This phenomenon significantly modifies the nonlinear response of the medium. The system of wave equations for two components for the vector potential is supplemented by a term that takes into account the effect of polymers on an extremely short optical pulse. The dependences of the output pulse parameters on the degree of anisotropy and concentration of nanotubes in the composite are established. It is shown that by controlling the orientation of carbon nanotubes, it is possible to purposefully influence such parameters of an extremely short optical pulse. This opens up significant prospects for the design and creation of new active elements, such as ultrafast optical shutters, modulators, laser radiation limiters and sensors based on controlled nonlinear properties of materials.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):26-33
26-33
Features of defective structure of active-uneline crystals of double duality LiTaO3:Cr:Nd and their manifestation in the infrared absorption spectra in the field of valence vibrations of hydrogen atoms of ОН—— groups
Abstract
The defect structure of a series of LiTaO3 crystals, LiTaO3:Cr (0,005 wt.%), LiTaO3:Cr(0,06):Nd (0,20 wt.%), LiTaO3:Cr(0,09)Nd (0,25 wt.%), LiTaO3:Cr(0,1):Nd (0,25 wt.%), LiTaO3:Cr(0,2):Nd (0,45 wt.%), was studied using infrared absorption spectra in the frequency range of stretching vibrations of hydrogen atoms in OH hydroxyl groups. It was found that the spectra of all crystals contain lines with frequencies in the ranges of 3462-3464 and 3476-3480 cm-1, corresponding to stretching vibrations of hydrogen atoms in OH hydroxyl groups. Such minor differences in the line frequencies are due to differences in the stoichiometry of the crystals (the ratio R=[Li]/[Ta]) and the formation of complex defects (VLi—)-OH. It was found that the absorption band with a frequency of ≈ 3504 cm-1 is associated with the appearance of complex defects CrLi2+-OH-CrTa2-. The Klavier method was used to determine the volume concentration of OH- groups in the crystals, which is maximum for the LiTaO3:Cr(0,09)Nd (0,25 wt%) crystal due to the presence of two types of complex defects (Cr2+Li)-OH-(Cr2-Ta) and (VLi—)-OH.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):34-43
34-43
Hysteresis behaviours of niobium containing barium titanate crystals
Abstract
The paper presents the results of an experimental study of switching processes in niobium- containing BaTiO3 crystals. It is shown that increasing the niobium concentration in BaTiO3:Nb5+ in the range from 0,1 to 0,9 mol.% leads to an increase in the values of the switchable polarization of crystals by 20-30% compared to pure barium titanate. Coercive fields also increase: the maximum increase in the coercive field by 95% is observed for crystals with the niobium concentration of 0,9 mol.%. The field frequency has a significant effect on the switching processes: with an increase in the frequency of the repolarizing field E = 9,6ꞏ104 Vꞏm-1, the values of the switched polarization decrease monotonically to frequencies of the order of 500 Hz, and the dielectric viscosity coefficient — to 200 Hz. If we continue to increase the field frequency, the values of the polarization and the dielectric viscosity coefficient remain practically unchanged. It was found that in the frequency range from 30 Hz to 90 Hz, the domain structure of the BaTiO3 crystal actively participates in its repolarization processes.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):44-51
44-51
Optical deposition of nanoparticles in dense nanosuspensions
Abstract
Studying concentration profiles induced by sedimentation is an effective way to obtain an equation of state of a colloidal suspension, to study fine details of the phase diagram and obtain information about the nature of metastable phases. Optical sedimentation methods have a number of advantages over the gravity method or centrifugation. In particular, an effective method of sedimentation in transparent nanosuspensions provides the use of the light pressure. In the case of nanoparticles, the light pressure force can exceed gravitational ones by orders of magnitude even when using continuous radiation sources. Calculation of the concentration profile for sufficiently high radiation intensities, when the volume fraction of nanoparticles at the bottom of the cuvette can reach unity, requires taking into account the interaction (repulsion) of nanoparticles. In this paper, the simplest model for taking into account the finite volume of the nanophase, the hard sphere model, is considered. As a result of the analytical solution of the problem of light-induced mass transfer, an expression is obtained that allows calculating the steady-state concentration profile. The proposed model demonstrates the need to take into account the finite volume of nanoparticles when calculating the parameters of optical deposition in dense nanosuspensions at high (superthermal) radiation intensities. The results obtained are of interest for the development of new methods for obtaining nanomaterials, photonic crystals and chemical sensors, as well as for improving the methods of optical diagnostics of nanomaterials.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):52-58
52-58
Light induced lens in a transparent nanosuspension
Abstract
Self-focusing of radiation is usually considered as a nonlinear effect in a medium with a positive coefficient of the cubic nonlinearity. Nanosuspensions have such nonlinearity due to electrostrictive flows of nanoparticles in a non-uniform light field. The description of this type of nonlinearity is traditionally limited to the consideration of the mode of weak intensities of the light field. In this case, the quasi-stationary change in the concentration of nanoparticles is directly proportional to the radiation intensity. Therefore, the analysis of the self-action of radiation corresponds to the classical case. In this paper, we analyze the self-focusing mode of a Gaussian beam in a transparent nanosuspension at high radiation intensities, when a response of the medium no longer corresponds to the cubic nonlinearity. A solution is given to the nonlinear stationary problem of light-induced transfer of nanoparticles in a liquid medium under the action of electrostrictive forces at high radiation intensities. The obtained result demonstrates an exponential dependence of the change in the concentration of nanoparticles on the radiation intensity. This is fundamentally different from the mode of weak intensities, where the change in concentration is linearly dependent on the intensity. In the classical case of the cubic nonlinearity, the self-focusing mode is determined by the total beam power. The considered model demonstrates a significant decrease in the critical self-focusing power at high radiation intensities, the use of which is more preferable for the experimental implementation of the self-focusing mode.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):59-66
59-66
Study of the properties of the Heusler alloy Ni-Mn-Ga-Cu systems in different structural states
Abstract
The paper presents the results of studying the microstructure, the magnetic domain structure and some magnetic properties of NiMnGaCu alloy samples in initial and deformed states. It has been shown that carrying out deformation-thermal treatment, including homogenizing annealing, extrusion with subsequent vacuum annealing, contributes to a change in the microstructure of the initial alloy (reduction in the size of crystallites and martensitic plates). Magnetic domains on the surface of the samples were visualized by magnetic force microscopy, and a substructure of secondary microtwins with their own magnetic domain structure was revealed. A study of the field dependences of the magnetization of the initial and deformation-heat-treated samples allows us to conclude that both samples have the same saturation magnetization value. Magnetometric measurements demonstrate an insignificant shift in the phase transition temperature towards lower temperatures for the deformed sample. The maximum values in the temperature dependences of the magnetocaloric effect for the original and deformed samples strictly correspond to phase transitions.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):67-76
67-76
Magnetic viscosity and magnetic reversal processes of the heterogeneous Gd0,85Zr0,15(Co0,7Cu0,09Fe0,21)6,0 alloy
Abstract
The results of experimental studies of the magnetic properties and relaxation processes of the alloy Gd0,85Zr0,15(Co0,7Cu0,09Fe0,21)6,0 are presented in this paper. The studied sample were subjected to a special heat treatment which allowed the formation of a certain nanostructure that affects the hysteresis properties of the material and allows to achieve a highly coercive state. The critical operating temperatures of the alloy were determined according to magnetic measurements at different temperatures performed on a vibrating magnetometer. It was found that thermal cycling of the sample in the range from 22°C to 400°C does not lead to changes in its magnetic properties at room temperatures. The investigations of magnetic viscosity effects allow us to conclude that the relaxation processes in the Gd-Zr-Co-Cu-Fe alloys are primarily due to the thermally activated overcoming of energy barriers by the domain walls, created by their complex and unique nanostructure. Metastable states of the domain structure near the barriers and their slow «release» under the influence of the thermal fluctuations result in the observed slow change in magnetization over time after a change in the external magnetic field and/or temperature.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):77-91
77-91
Nanostructure and ferroelectric properties of nanoscale BaTiO3/SrRuO3/MgO(001) films
Abstract
High-quality ferroelectric BaTiO3/SrRuO3/MgO(001) heterostructures with BaTiO3 film thicknesses ranging from 36 to 360 nm were synthesized using high-frequency cathode sputtering in an oxygen atmosphere. A comprehensive study of their crystal structure, surface morphology, piezoelectric and ferroelectric properties was conducted using X-ray structural analysis and scanning probe microscopy. It was established that all the obtained films are single-phase and heteroepitaxial. X-ray diffraction measurements revealed a significant deformation of the unit cell, which reaches a maximum (~4,4%) for the thinnest films and decreases with increasing thickness. It was shown that the surface roughness of the films, estimated from scanning probe microscopy data, systematically increases with thickness, following a scaling law. Piezoresponse force microscopy demonstrated the possibility of local polarization switching in the films and revealed an increase in the magnitude of the residual piezoelectric response with the growth of the ferroelectric layer thickness. The surface potential of the films was measured by Kelvin probe force spectroscopy, and a tendency for it to decrease with increasing thickness was established. The paper discusses the reasons for the observed patterns. The obtained results are important for understanding size effects in nanoscale ferroelectric films and their applications in microelectronics and functional devices.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):92-101
92-101
Features of dynamic effects in irradiated metals
Abstract
A theoretical analysis of edge dislocation ensemble slip in irradiated metal with a high concentration of nanoscale defects (prismatic dislocation loops) is performed. The problem is solved within the framework of the theory of dynamic interaction of defects. High strain rate deformation occurs in the irradiated metal under intense external impact. The dissipation mechanism consists in the irreversible transition of the energy of external impact into the energy of transverse oscillations of a dislocation in the slip plane. The efficiency of this mechanism depends on the presence of a gap in the spectrum of dislocation oscillations. In our case, the spectral gap appears as a result of the collective interaction of dislocations. Analytical expression for the dependence of the dynamic yield strength on dislocation loop concentration and the dislocations density in the irradiated metal is obtained. The effect of dry friction of dislocations is predicted. It consists in the fact that the force of dynamic drag of dislocations by circular dislocation loops does not depend on the dislocations velocity. Accordingly, the contribution of dislocation loops into the dynamic yield strength of irradiated metal does not depend on the strain deformation rate. Calculated estimates of the contributions of dry friction of dislocations into the dynamic yield strength of irradiated metals are made. The value of this contribution can reach 108 Pa.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):102-108
102-108
Fluorination of CVD graphene films by inductively coupled plasma CF4
Abstract
Synthesis of nanometer-thick dielectric films is one of the key tasks in nano- and optoelectronics, which is associated with growing requirements for miniaturization and functionality of devices. This paper presents the results of a study of optical and electrical properties of graphene fluorinated by inductively coupled plasma CF4. Fluorination was carried out in plasma with a power of 125 to 200 W for duration of up to 1 min. Two methods of arranging samples in the plasma chamber were used: 1) with a graphene film facing plasma and 2) with a substrate facing plasma. The methods of Raman spectroscopy, X-ray energy-dispersive spectroscopy, and current-voltage characteristics were used in the study. It was shown that the direct plasma action on the samples in position 1 results in graphene etching until the film is completely removed. In position 2, no intensive etching is observed during treatments lasting up to 1 min. In this case, fluorination of the graphene film occurs. As a result, the ratio of the number of fluorine atoms to carbon reaches a value of ~0,2. As a result of plasma treatment, there is a significant increase in the electrical resistance of graphene. The increase in surface resistance was from several kΩ/sq for the initial graphene to hundreds of GΩ/sq and tens of MΩ/sq for the samples subjected to plasma action in positions 1 and 2, respectively. The increase in the electrical resistance may be due to both the appearance of defects during plasma treatment and the fluorination process, which forms sp3-hybridized C-F bonds that distort the flat structure of graphene. Repeated conductivity assessments carried out after three weeks showed a decrease in resistance by two orders of magnitude for samples treated in plasma in position 2. This decrease may be due to the processes of defluorination and restoration of the flat structure of graphene.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):109-117
109-117
Effect of modifiers on the structure and polarization state of lithium sodium niobate ceramics
Abstract
In this work, ceramic Li0,1Na0,9NbO3 samples (pure and with modifying additives (5%) SrTiO3 or LiTaO3) were obtained by solid-phase synthesis. If the grain size of pure lithium sodium niobate and modified (5% of SrTiO3) is practically the same, then the inclusion (5% of LiTaO3) in the composition of Li0,1Na0,9NbO3 ceramics leads to a significant spread in the grain size. In this case, grains of several times larger size are released. Based on analysis of the elemental composition, it was established that the inclusion of SrTiO3 and LiTaO3 modifiers in the composition of Li0,1Na0,9NbO3 differs significantly. In the first case (for SrTiO3), we can talk about the homogeneity of inclusion at the nanostructural level, whereas LiTaO3, despite its presence throughout the entire volume of the sample, is included in the composition of Li0,1Na0,9NbO3 in blocks. Measurement of pyroelectric properties showed that only the introduction of SrTiO3 (5%) as a modifier leads to the possibility of obtaining a uniformly polarized state in the LNN ceramic sample, which is important for practical application.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):118-124
118-124
Exploding wires synthesis of dispersed aluminum oxide powders for extrusion 3D printing of porous product
Abstract
The influence of the parameters of electroexplosive synthesis of Al2O3 particles on their average size and phase composition was studied. The equivalent diameter of the wires and the buffer gas pressure at a constant value of energy introduced into the wires were varied synthesis parameters. An increase in the equivalent diameter of the wires from 0.25 to 0.50 mm leads to an increase in the average particle size from 81 to 92 nm. An increase in the buffer gas pressure from 0,1 to 0,4 MPa at an equivalent wire diameter of about 0,50 mm leads to an increase in the average particle size from 76 to 106 nm. An increase in the buffer gas pressure leads to the formation of an additional mode on the particle size distribution curve with a maximum in the region of 30-40 nm. The crystal structure of the samples obtained at different buffer gas pressures corresponds to the θ — and γ — phases for Al2O3. Al2O3 powders obtained by electrical explosion of wires can be used to manufacture porous products by extrusion 3D printing.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):125-134
125-134
Phase formation in the Nb-Cu-Ti system formed on a substrate by vacuum-arc plasma-assisted method
Abstract
Multilayer systems including interfaces between different metals are considered to be a new family of materials with a wide range of applications (electronic devices, materials for aerospace and nuclear installations, where exceptional mechanical, electrical and thermal properties are required under conditions of high deformation and high-temperature thermal cycling). The aim of this work was to study the elemental and phase composition, substructure, mechanical, and tribological properties of binary (Nb – Cu) doped with titanium atoms films formed on a solid substrate by the vacuum-arc plasma-assisted method. Experiments on the deposition of thin films and coatings were carried out on the ion-plasma setup «KVINTA» developed in the Laboratory of Plasma Emission Electronics of the Institute of High-Current Electronics of the Siberian Branch of the RAS. It is shown that during the formation of the Nb – Cu films, they are doped with titanium atoms entering as a result of diffusion from the substrate (Grade 2). It was established that the films are a layered two-phase (copper and niobium) amorphous-crystalline material. The microhardness of the films is 6,8 GPa, which is many times (more than 5 times) higher than the microhardness of polycrystalline niobium; the wear parameter (the value reciprocal of wear resistance) k = 2,2×10-5 mm3/N∙m, which is 24,6 times less than the wear parameter of pure copper.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):135-147
135-147
On the possibility of using naphthalene crystals in the production of liquid organic scintillators for use in neutrino physics
Abstract
This study reports a comprehensive investigation of novel scintillation systems based on syntin and dodecane, incorporating naphthalene and 2,5-diphenyloxazole as primary additives. For the first time, it was demonstrated that optimizing the naphthalene concentration and achieving direct spectral matching with the sensitivity range of photodetectors can result in a light yield surpassing that of standard pseudocumene-based solutions. At a naphthalene concentration of 100 g/L, excimer formation was observed, contributing additional emission components and broadening the fluorescence spectrum. This approach eliminates the need for secondary wavelength shifters, thereby reducing energy losses and improving energy resolution. The measured relative light yield reached up to 120 % of the reference pseudocumene solution, corresponding to approximately 15,600 photons/MeV for dodecane–naphthalene mixtures. The novelty of this work lies in the experimental validation of the feasibility of developing highly efficient liquid scintillators with a simplified composition and record-high light output without secondary shifting additives. The results highlight the potential of these materials for applications in ionizing radiation detection, including neutrinoless double-beta decay experiments.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):148-160
148-160
Complexity analysis of magnetic domain structure of high- and low-anisotropic compounds bulk samples
Abstract
For uniaxial crystals bulk samples with known structural and magnetic characteristics, it is possible to predict the magnetic domain structure configuration and its elements geometrical parameters. However, this estimation only provides information about the final structure on the basal plane, while the formation features are not considered. In this study, we present a complexity analysis of the domain structure of high- and low-anisotropic compounds, based on its stray field investigation, as well as within the framework of fractal geometry methods. The conducted analysis allowed us to estimate the domain structure complication level through the formation process from bulk domains to the basal plane surface structure. Additionally, based on the scanning probe microscope tips signal spatial distribution, the stray field fractal analysis was carried out. As a result of the obtained data comparison for high- and low-anisotropic compounds, it was shown that the objects with qualitatively different domain structure configurations, but similar formation patterns, have close structure complexity parameter values. At the same time, objects with a simplified structure and a reduced additional domain number have lower values for the structure complexity parameter.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):161-171
161-171
Influence of stoichiometry of aluminum nitride films composition on the dielectric response
Abstract
The effect of non-stoichiometry of thin single-crystal layers of aluminum nitride (AlN) on their structure and dielectric properties was investigated. Thin AlN layers were grown by chloride-hydride epitaxy on a silicon substrate with a nanoscale buffer layer of silicon carbide grown by solid state substitution (SiC/Si(111)). Phase analysis of the structures was carried out by X-ray structural analysis using X-ray DRON-7 diffractometer, and the microstructure and composition of cross sections were studied using Lira3 Tescan scanning electron microscope. The aluminum nitride layers differed in composition — with strong non-stoichiometry (~ 18%) and with a composition close to stoichiometry (~ 4%). It was revealed that the increase in non-stoichiometry leads to an increase in the interplanar distance of the hexagonal (wurtzite) structure and deformation of the crystal lattice of thin layers of aluminum nitride. For non-stoichiometric films, an increase in relaxation phenomena of permittivity in the low-frequency region of the spectrum and an increase in dielectric losses by 1.5-2 times in the studied frequency range were observed as well as under the conditions of applying bias fields. It is assumed that the presence of asymmetry in the capacitance-voltage characteristics is due to a contribution of the volume-charge polarization and a change in the magnitude of spontaneous polarization.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):172-181
172-181
Effect of annealing time on the structural and electrophysical properties of strontium ferromolybdate films
Abstract
Thin films of strontium ferromolybdate Sr2FeMoO6 are a promising material for spintronic applications. To comprehensively study the relationship between structure, electrophysical properties, and magnetic characteristics of films deposited by ion-beam sputtering on Al2O3 substrates followed by reductive annealing at 900°C, a set of modern microscopic and spectroscopic techniques was employed. Specifically, Raman spectroscopy, atomic force microscopy, conductive microscopy, Kelvin probe force microscopy, and magnetic force microscopy were used to investigate in detail how different annealing durations (0.5, 1, and 1.5 hours) affect key parameters of the material. It has been found that the duration of annealing significantly influences the surface roughness, electrophysical properties, and most importantly, the formation of magnetic domain structures in Sr2FeMoO6 films. Analysis of the obtained data revealed that optimal structural characteristics are achieved after annealing for 1 hour, while the best magnetic domain structure is observed in samples subjected to annealing for 1,5 hours. These results are important for optimizing the synthesis process of Sr2FeMoO6 films with improved characteristics, which contributes to more efficient use of this material in various spintronic devices.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):182-189
182-189
Microstructure and properties of metastable nanostructured alloys processed by severe plastic deformation
Abstract
A brief literature review of foreign studies and our own experimental data on the use of severe plastic deformation by equal-channel angular pressing for the formation of a nanostructure in bulk metastable alloys of various natures is presented. It is shown that such materials, due to bulk phase and structure transformations (deformation dissolution, artificial and natural aging, polymorphic) have greater practical potential for improving mechanical and physical properties compared to pure metals or solid solutions. The article considers the structural features, physical and mechanical properties of structural alloys based on aluminum, titanium and hard magnetic alloys based on the Nd(Pr)2Fe14B compound after severe plastic deformation and additional annealing. In the aluminum alloy Al-Fe with the absence of iron solubility under normal conditions, severe deformation allows dissolving up to 0.6% Fe, obtaining a composite structure and increasing the strength properties many times. In commercially pure titanium VT1-0 and titanium alloy VT6 subjected to equal-channel angular pressing, low-temperature post-deformation annealing causes aging, accompanied by an increase in microhardness and strength. In the cast hard magnetic alloy Pr-Fe-B-Cu, refinement is also observed during equal-channel pressing and an increase in magnetic hysteresis properties.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):190-202
190-202
Crystal structure and dispersed composition of multicomponent (NiFeCoCuZn)xOy oxide nanoparticles obtained by joint exploding wires
Abstract
In this work, preparation of powders of multicomponent (NiFeCoCuZn)xOy nanoparticles by the method of combined electrical explosion of wires in an atmosphere of Ar + 25 mol % O2 gases is demonstrated. Heating of wires with a current pulse with a density of 3,15×107 A/cm2 at a buffer gas pressure of 0,15 MPa leads to the formation of nanoparticles of multicomponent oxide with an average size of about 54 nm. The particle size distribution is described by the normal-logarithmic law. The particles have the spherical shape. The synthesized sample contains two crystalline structures corresponding to rock salt (Fm3m, a = 4,213 Å) and spinel (Fd3m, a = 8,389 Å). The results of the study show that the crystal structure of (NiFeCoCuZn)xOy nanoparticles can be optimized by both changing the ratio of divalent and trivalent metals in the wire explosion products and changing the thermodynamic conditions for the formation of nanoparticles.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):203-210
203-210
Crystal structure and dispersed composition of multicomponent NiFeCoCrCuAlMo and NiFeCoCrCuAlMoW alloy nanoparticles obtained by joint exploding wires
Abstract
Nanoparticles of multicomponent NiFeCoCrCuAlMo and NiFeCoCrCuAlMoW alloys were synthesized by combined electrical explosion of wires of various metals/alloys in an argon atmosphere. Transmission electron microscopy and X-ray diffraction analysis were used to determine the structural characteristics of the nanoparticles. The average particle size is about 50 nm (with the ratio of the energy E introduced into the wires to the total sublimation energy of the wires ΣEc of the order of 1,6), and the crystal structure is represented by the bcc and fcc phases of substitution solid solutions and the bcc phase corresponding to a substitution solid solution based on a refractory metal. It has been suggested that greater homogeneity of the elemental and phase composition of nanoparticles in multicomponent NiFeCoCrCuAlMo and NiFeCoCrCuAlMoW alloys can be achieved by varying the energy parameters of the combined electrical explosion of wires. Thus, the research results indicate the need to optimize the synthesis parameters to obtain nanoparticles with a desired elemental composition and crystal structure.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):211-220
211-220
Distribution of components of binary metal melt during exposure in capillaries of complex shape
Abstract
The results of several different experiments on the study of the process of stratification and diffusion of components of a binary tin-lead metal melt located in «capillaries» of a non-wettable material and complex shape are presented. The diffusion process was studied with the direct mutual dissolution of pure initial components from the «lead below, tin above» state in cells that allow lead atoms to spread both upward and downward in the volume of liquid tin. The «stratification» experiment was carried out in a flat capillary with an internal defect included, which made it possible to create a transverse cavity up to 0,5 mm deep in the lower part of the wide face of the sample, completely overlapping the width of one of the sample planes. The quantitative analysis of the composition of the samples was carried out by the X-ray-fluorescence method according to a pre- constructed calibration scale. In the metal melt, experimental results made it possible to reveal the existence of a second mass transfer mechanism, in addition to diffusion, consisting in the flow of lead along the boundary between the liquid sample and the non-wettable wall of the «capillary». The results of the diffusion experiments fully correspond to the data on stratification in a planar capillary, as well as to previous studies.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):221-230
221-230
The effect of the diameter on the distribution of components of metal melt over the height of a capillary
Abstract
Binary and more complex metallic melts are characterized by instability of the composition in the melt height. This effect is expressed in the fact that the initially homogeneous melt, after being held for a fairly short time in a vertical, non-wettable vessel (crucible or capillary), acquires a gradient in the concentration of components in height, while the heavy component is distributed over the height of the crucible according to a barometric dependence corresponding to the distribution of large particles (clusters). This fact is one of the reasons for the cluster structure of melts. Analysis of the experimental results leads to the conclusion that a second mass transfer mechanism exists in liquid metals, consisting in the flow of components within the interfacial layer between the capillary wall and the melt, acting simultaneously with diffusion in the melt volume. A number of special experiments unequivocally confirm this hypothesis. The experimental results presented in this paper have shown that the flow features of the interfacial layer make it possible to create a stationary state in the volume of a binary melt with a concentration gradient of the components, which is in principle impossible with a purely diffusive mass transfer mechanism. This result may be treated as a direct proof of the existence of a second mechanism of the mass transfer in metal melts.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):231-239
231-239
Simulated annealing method in variational quantum algorithms
Abstract
Variational quantum algorithms are the only quantum algorithms that are currently used in hybrid quantum-classical devices to solve rather practical than modelling problems in condensed matter physics, quantum chemistry, and machine learning. In this paper, a new variational quantum algorithm is analysed in detail, implemented in codes and tested. Its distinctive feature is the use of the simulated annealing algorithm to minimize the objective function (energy) as well as a new type of unitary ansatz with multi-qubit interaction. The quantum part of the algorithm is emulated on a classical computer, and the efficiency of the algorithm is estimated by the number of iterations. To test the algorithm, we choose the problem of finding the ground state of the electronic structure of the hydrogen molecule at the equilibrium distance between protons. The Hamiltonian in the Born-Oppenheimer approximation is modeled by the Hamiltonian of a 4-qubit system in the Pauli basis. The universal ansatz for the problem is constructed taking into account the symmetry of the Hamiltonian as a composition of the exponentials of Pauli operators. It depends on 4 parameters, and the corresponding energy has twelve local minima. The algorithm, implemented as a modular program in Python using both the direct annealing method and the dual_annealing function of the Sci-py library, showed high efficiency in comparison with the algorithm based on the standard ansatz and the gradient descent method.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):240-249
240-249
Interfacial energy of palladium crystals at the boundary with nonpolar organic liquids
Abstract
Organometallic compounds of palladium and palladium nanocrystals play a significant role in chemical industry, medicine, hydrogen storage and transportation, and other fields. The introduction of technology for implanting chips or other devices into a living organism requires understanding the physico-chemical processes and properties at the interface of organic substances with metals. Devices implemented in this way can monitor the biological parameters of the body, for example, heart rhythm, glucose levels, as well as deliver medications or stimulate the nervous system. Of particular interest are neural interfaces implanted in the brain, which control various devices, for example, a smartphone or computer using thought. It is of interest to study the properties of liquid organic hydrogen carriers that include palladium nanoparticles as catalysts and allow safe storage, transportation and controlled release of hydrogen. In this work, the values of the interfacial energy at the boundaries of the faces of a palladium crystal with organic liquids are obtained using electron statistical method, taking into account the dispersion interaction of Wigner-Seitz cells at the interface, as well as the polarization of metal ions and organic liquid molecules. The dependences of the interfacial energy and the corrections to the interfacial energy on the orientation of the metal crystal and on the dielectric constant of liquid are obtained. It is established that the dispersion correction increases, and the polarization correction decreases, the interfacial energy. The highest value of the interfacial energy is characteristic of the face (111) and the lowest value for the face (110).
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):250-258
250-258
Thermodynamic simulation of chemical segregation in binary metallic nanoparticles using the Langmuir– McLean equation
Abstract
A method has been developed and tested for thermodynamic simulation of the surface segregation in binary nanoalloys. The method is based on the numerical solution of a system of two equations: the Langmuir-McLean equation and the mass balance equation for a two-cell system represented by the central region (core) of a nanoparticle and its surface layer (shell). Apparently, for the first time, when applying the Langmuir-McLean equation, the dependence of the segregation heat on the composition of the core and shell of the two-cell nanoparticle model has been taken into account. The developed approach has been applied to predict the surface segregation in binary Ag-Cu and Ni-Cr nanoparticles. The obtained results predict the surface segregation of Ag for the Ag-Cu nanoalloy and the surface segregation of Cr for Ni-Cr nanoparticles. We have shown that the surface segregation decreases with decreasing the nanoparticle size (the effect of the core depletion as a source for the segregating component) and with increasing temperature. The results of thermodynamic prediction of the surface segregation based on the Langmuir-McLean equation are consistent with both the results of thermodynamic simulation based on the solution of the Butler equation and with our results of atomistic simulations obtained earlier.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):259-266
259-266
Estimation of the parameters of nonequilibrium grain boundaries from the high-temperature background of grain boundary internal friction
Abstract
The physical processes leading to the formation of nonequilibrium grain boundaries in nanocrystalline and ultrafine-grained materials are considered. The problem is solved for a two-dimensional diffusion equation on a boundary segment exposed to variable compressive stresses. The vacancy distribution and the corresponding normal tension in the segment are found. From the consideration of vacancy dynamics, the rate of mutual displacement of grains in the normal to the boundary direction and the amount of internal friction are determined. Internal friction has the character of a high-temperature background. The effect of stress adjustment is taken into account. The process of atomic relaxation of the boundary structure over time is discussed. The change in relaxation energy is shown with a change in a complex parameter, including frequency, grain size, activation energy, and temperature. From the graph of the dependence of the logarithm of the product of internal friction on temperature on the reverse temperature, the activation energies on the high- and low-temperature parts of the process are found. It is shown that at pre-melting temperatures, areas with the highest activation energy may appear. A method for determining the activation energy of internal friction at equilibrium and nonequilibrium boundaries is considered. The method of grain size estimation is discussed. The relaxation time of the atomic structure of the boundary can be determined from the change in the amount of internal friction over time.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):267-275
267-275
Application of the fractal state equation to calculate helium isobars at high temperatures and pressures
Abstract
The paper presents calculations of the state equation (isobars) of helium-4 in the pressure range from 10 to 100 MPa and the temperature range from 600 to 1500 K using the fractal state equation and the Fract EOS software. It was discovered that the temperature dependence of the fitting parameter α for the temperatures above 400 K weakens sharply and practically disappears approaching to 600 K. For helium-4, this allowed to approximate the dependence of α on density by a polynomial and to use it in calculations at temperatures above 600 K. For calculation of isobars, a set of isotherms with a small temperature step was calculated. Then, a point with the required pressure was selected on each isotherm. Obtained results show good agreement with literature data. In addition, for the specified temperatures and pressures, the isobars of the classical equation of state and the Redlich-Kwong equation of state were calculated. A comparison of the relative calculation error showed a significant advantage of the fractal equation of state.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):276-283
276-283
Calculation of the temperature dependence of the magnetic susceptibility of subnanosized titanium dioxide clusters
Abstract
Subnanosized clusters containing paramagnetic titanium and oxygen ions can be considered as fragments of the surface of nanocrystalline titanium dioxide. The analysis of the temperature dependence of the magnetic susceptibility of titanium dioxide clusters makes it possible to study the manifestations of surface magnetic states and identify the type of magnetic ordering. Using the density functional theory method in the M06/6-31G(d, p) approximation, a quantum chemical calculation of the equilibrium geometry of (TiO2)n (n = 2-5, 13, and 15) clusters with a full or predominant proportion of surface atoms was performed. It is established that for all (TiO2)n clusters, the singlet electron configuration is the ground state. To assess the thermal stability of (TiO2)n cluster structures and study the effect of temperature in the range of 10-900 K in 50 K increments, calculations were performed using the ab initio method of molecular dynamics and the atom-centered density matrix propagation scheme. The length of each molecular dynamics trajectory was 1 ps with a time step of 1 fs. For each temperature, the magnetic susceptibility tensor was calculated using the coordinate invariant atomic orbitals (gauge including atomic orbitals) method in the approximation M06/6-31G(d, p). It is shown that the temperature dependence of the values of the isotropic magnetic susceptibility has a maximum at temperature Tmax. At T > Tmax, there is a decrease in the temperature dependence of the magnetic susceptibility of (TiO2)n clusters. It has been established that the main magnetic state of (TiO2)n clusters is an antiferromagnetic singlet. The importance of the anisotropy of magnetic susceptibility for the TiO2 molecule and clusters of (TiO2)n is shown.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):284-292
284-292
Adsorption deformation of Na-montmorillonite during interaction with methanol vapours
Abstract
Classical ideas about the adsorption process have always been based on the fact that the adsorbent remains inert and does not change its size when interacting with gases or vapors. Its role is limited to creating an adsorption field where the adsorbate molecules fall. It is on the basis of this principle that the well-known adsorption equations of Henry, Langmuir, Fowler-Guggenheim, Brunauer-Emmett-Teller and others were derived. However, modern experimental studies show that adsorbents are deformed in the adsorption process. This fact significantly changes the entire picture of the consideration of this phenomenon. For example, when the geometric dimensions of the pores of the adsorbent change during deformation of the latter, the adsorption field into which the adsorbate molecules fall changes significantly. And this affects the value of the calorimetric heat of adsorption registered during the studies. Thus, the adsorbent is an equal participant in the adsorption process along with the adsorptive, and the adsorption system should be considered as a two-component one. In this regard, when conducting adsorption studies, a comprehensive approach is needed, including taking isotherms, measuring calorimetric heats of adsorption, and conducting dilatometric experiments to study the adsorption deformation of adsorbents. Such a comprehensive approach was used for the Na-montmorillonite – methanol vapor system. The differential heat and adsorption isotherm at T = 293 K were obtained using a Calvet-type microcalorimeter and a McBain-Bakr microbalance. The adsorbent deformations were measured using a highly sensitive dilatometer. The main part of this dilatometer was a linear differential transformer, the core of which was connected to the adsorbent by means of a rod. Any changes in the geometric dimensions of the adsorbent changed the position of the core in the transformer, which affected the signal taken from the secondary winding of the transformer. Having calibrated the dilatometer, the adsorption deformation of the adsorbent was determined. Such a comprehensive approach allowed us to significantly detail the description of the adsorption process for the studied system.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):293-299
293-299
Hysteresis phenomena in the study of adsorption deformation of adsorbents
Abstract
As is known, adsorption hysteresis is a phenomenon that occurs in physical adsorption processes. In this case, the amount of adsorbed substance differs when adding gas (or vapor) and when removing it, i.e. the adsorption branch does not coincide with the desorption branch during experimental measurement of the adsorption isotherm. The literature provides various reasons for this phenomenon: surface and volume phase transitions in the adsorbate; capillary effects in pores of a certain geometry; elastic and plastic deformation of the adsorbent; the presence of a potential energy barrier for the penetration of the adsorbate into the pores, etc. It is clear that in the case of capillary condensation in the pores of the adsorbent, irreversibility of adsorption is indeed characteristic, i.e. the adsorption and desorption curves do not coincide, and these curves form an adsorption hysteresis loop. It is assumed that in other cases the key role in this effect is played by the adsorption deformation of the adsorbent. The use of a modern highly sensitive dilatometer for recording the curves of adsorption and desorption deformation of the adsorbent, along with the traditional measurement of adsorption isotherms, allows us to study this problem in detail. The results of such a comprehensive approach are presented in this paper. Organo-substituted Pyzhevsky montmorillonite and organo-substituted synthetic fluorohectorite were used as adsorbents. Their interaction with hexane and benzene vapors was studied. A detailed analysis of the obtained data is carried out, allowing us to state that the adsorption deformation of the adsorbent plays a key role in the adsorption hysteresis.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):300-307
300-307
Surface energy and electron work function of aluminum and lead crystal faces
Abstract
Technological processes and operational properties of materials largely depend on the surface properties of metals. Aluminum and lead are widely used in various industries, but there is still a wide range of experimental data on their surface energy and electron work function. Changes in these characteristics with increasing temperature have not been studied in practice. In this regard, the surface energy of the faces of aluminum and lead crystals was evaluated using the electronic statistical method, taking into account the contributions of dispersion, polarization, and oscillation corrections, as well as thermal effects. The analytical relationship between the surface energy and the electron work function of densely packed single crystal faces allowed us to evaluate the effect of temperature on the anisotropy of the properties under study. A comparison of changes in the tensile strength and surface energy of aluminum and lead polycrystals has shown the possibility of developing an analytical relationship between these values, which will make it possible to predict the behavior of metals and alloys, including materials with reduced dimensionality. However, in addition to the relationship between the surface energy of polycrystals, the cohesion energy, and the tensile strength, it is necessary to take into account other components of the fracture energy of materials.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):308-316
308-316
On the energy bandgap in mesoporous semiconductors
Abstract
In this paper, the dependence of the energy bandgap of a mesoporous semiconductor on geometric characteristics (volume and shape) of pores distributed in the material has been analyzed. The obtained estimates demonstrate that the well-known effect (being characteristic of nanoscale particles), which consists in a significant dependence of the bandgap on the size and shape of a particle, can also be realized in mesoporous materials (the pore size being from 5 up to 50 nm) while the mesoporous materials themselves can be of macroscopic dimensions. Using mesoporous CdSe as an example, it has been shown the reducing the pore size and «complicating» the pore shape result in a notable increase in the energy bandgap. The results have been obtained using the cohesive energy-based model, being verified experimentally for CdSe nanoparticles. Geometric characteristics of pores have been determined in the framework of the fractal-geometry approach by the values of their effective diameter and fractal dimension.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):317-327
317-327
One more peculiarity of high-temperature phase equilibria in nanoparticles of the Crx-W1-x heavy pseudo-alloy
Abstract
Thanks to a unique set of physicochemical properties, nanoparticle-fabricated heavy tungsten pseudo-alloys with ultrafine-grained structures, manufactured using modern powder metallurgy methods, have become a subject of increased interest among researchers. In this study, within a thermodynamic approach, the features of the equilibrium phase composition of spherical Crx-W1-x nanoparticles of various diameters with different Cr fractions and a core-shell structure have been simulated in the temperature range between the liquidus and solidus. Examples of the dependencies of the equilibrium compositions of solid and liquid phases on the particle diameter have been obtained; it has been demonstrated that these dependencies significantly differ depending on the relative arrangement of solid and liquid phases within the core-shell structure. The results are complemented by an analysis of the effect of the initial composition, which consists in a dependence not only of the volume fraction of coexisting phases but also of their composition on the initial chromium content in a particle. To visualize some of these effects, some specific θ-diagrams have been applied, being previously suggested by the authors. A thermodynamic interpretation of the observed effects is presented based on three possible mechanisms for reducing the free energy of the system.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):328-338
328-338
Comparative analysis of the process of formation of fractal metal films: atomistic simulation
Abstract
In this paper, molecular dynamics method and the tight-binding potential were used to simulate a molecular beam epitaxy process for the formation of fractal metal films of copper subgroup elements (Ag, Au, Cu) on a solid surface of a more refractory metal, rhodium being selected. The author’s software product was used to simulate the molecular beam epitaxy. It was found that, with various parameters of the molecular dynamics experiment, it is possible to identify the transition from the formation of a family of island films with an irregular boundary to a more massive film, but with a symmetrical boundary. The conditions are described under which smaller island satellite films or films having a common boundary («sleeves») around one central film are formed. Under various conditions of the molecular dynamics experiment, the possibility of forming fractal structures in the island films under study was shown, and the fractal dimension was estimated in the software FractalSurface 2.0.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):339-352
339-352
Quantum-chemical calculation of zinc (II) compound with histidine: synthesis, structure, and properties
Abstract
The zinc coordination compound was synthesized with histidine. Complexometric and formolic titration methods were used in the study. This allowed to establish molar ratios in the complex, which was 1:2. Infrared spectroscopy confirmed the formation of coordination bonds. Infrared spectra of the synthesized compound measured in the range of 500-4000 cm-1 are given. For quantum chemical modeling, Hartree-Fock, and density functional methods were used in the B3LYP functional basis 6-31G (d, p). This made it possible to build and optimize the structure of the zinc histidinate complex, calculate its thermodynamic characteristics and infrared spectrum. Comparison of experimental and theoretical infrared spectra confirmed the adequacy of calculations of the density functional method for such systems. Using the X-ray phase analysis method, it was possible to calculate Miller indices and zinc histidinate unit cell parameters. For this, the dichotomy method was used. The average crystallite size is determined using the Selyakov-Scherrer method. The results of the study contribute to the understanding of zinc complexation mechanisms in biosystems. These studies are promising for the development of metabolic correction drugs and the prevention of pathologies caused by formation, including nanostructures.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):353-361
353-361
Effect of tight binding potential parameterization on the behavior of structural and thermodynamic characteristics of binary Au-Ag nanoparticles
Abstract
The results of atomistic modeling are largely determined by the chosen model of the computer experiment, including the choice of parameterization of the interatomic interaction potential. In this paper, using two parameterizations of the tight-binding potential a different set of parameters of monometallic bonds for Au-Au was chosen in the case when this element is one of the components of the binary nanoalloy Au-Ag. It is shown that when using the modified set, the melting temperature for the Au1500Ag1500 nanoparticle remains virtually unchanged, while the crystallization temperature slightly increases. It is found that the proportion of the local fcc phase when using set 1 of the potential parameters is lower than for set 2, and the presence of the local bcc phase is clearly identified after crystallization when using set 1, while the use of set 2 predicts the identification of the local bcc phase only in a narrow temperature range after crystallization. In addition, an analysis of the specific potential internal energy values shows that binary Au1500Ag1500 nanoparticles are more stable both in the initial configuration and after the thermally induced exposure cycle when using a modified set of parameters (set 2).
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):362-373
362-373
Predicting the aggregation stability of nanostructures based on polyVCL-polyVI copolymers: mesoscopic simulation
Abstract
Computer simulation of the aggregation behavior of thermosensitive copolymers of N- vinylcaprolactam (VCL) and N-vinylimidazole (VI) was performed in the framework of a coarse-grained model. Virtual synthesis of the copolymers from a monomer feed with different compositions was implemented using a Kinetic Monte Carlo method. At low conversions, statistical copolymers were obtained, while at high conversions, the copolymers contained a long block of VCL units. The aggregation behavior of the constructed copolymers was studied using Langevin dynamics in the solvent environment that is poor for the VCL units, which, in terms of the devised model, corresponds to the temperatures above the lower critical solution temperature for the VCL. It was shown that the aggregation of VCL blocks initially leads to the formation of nanoparticle-like nanostructures with a core-shell morphology, where the core is formed by VCL blocks and the shell is formed by VI blocks. The presence of a homopolymer VCL block increases the density of the core, while its length and the VCL content in the monomer feed affect the size of the shell. It was shown that the nanostructures formed at fVCL = 0,55 (VCL content in the monomer feed) have the highest aggregation stability. In this case, when the solvent is poor for the VCL, the mesoglobules are formed, consisting on average of 2-3 polymer chains. The polymers produced from monomer feed with higher VCL content form potentially aggregation-unstable nanostructures. Also, the polymers obtained at fVCL = 0,55 have the highest specific solvent-accessible area of VI units, which makes them a prospective basis for the development of thermally-switched catalysts.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):374-385
374-385
Simulation adsorption characteristics of fullerene dispersions
Abstract
Mechanisms of action of fullerenes on biological systems are not yet fully understood. Fullerenes can be modified to increase their efficiency and safety in medicine and drug delivery. Various ligands can be attached to them increasing their selectivity to certain types of cells or tissues. In this work, computer 3D modeling (ArgusLab 4.0.1) of colloidal suspensions and aqueous dispersions of fullerenes obtained by ultrasonic dispersion of compositions based on C60, vegetable oil (corn) and polyvinyl alcohol is carried out. The hydrodynamic radius of particles was measured on a Photocor Compact-Z particle size analyzer. The structure of the compounds is confirmed by spectrophotometry (UNICO 2100) and scanning electron microscopy (MIRA-LMH microscope from Tescan). The studies predicted that fullerene C60 can act as an effective inhibitor of leukotriene receptors in living systems. Leukotrienes are a group of biologically active substances, derivatives of arachidonic acid, which play an important role in the development of inflammation and allergic reactions, especially in bronchial asthma. Three-dimensional structures of the main types of leukotrienes and their molecular complexes with fullerene C60 were optimized. Analysis of the adsorption properties of fullerene derivatives opens up prospects for the creation of new biologically active compounds capable of specifically blocking leukotriene receptors and providing a therapeutic effect without the use of hormonal drugs.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):386-398
386-398
Effect of Nosé-Hoover thermostat on structural transformations in ternary Ti-Al-V nanoparticles
Abstract
An important criterion for verifying atomistic simulation results is not only the appropriate selection of the interatomic interaction potential and its parameters, but also the choice of thermostating methodology. This paper attempts to qualitatively assess the impact of the thermostat selection when modeling structural transformations in ternary Ti-Al-V nanoparticles. Two thermostats were used as basic ones: the Andersen thermostat and a soft stochastic thermostat, which is a Nose-Hoover thermostat with the addition of random noise to improve ergodicity. It was found that both thermostats, under the same simulation conditions for nanoparticles of the ternary Ti6Al4V alloy, predict similar structural transformations using different cooling rates (from 0,2 K/ps to 100 K/ps): at low rates, local FCC and HCP phases dominate, while with increasing cooling rate, the proportion of identifiable crystalline phases gradually decreases, and nuclei of icosahedral symmetry appear. The obtained patterns of structural transformations are reflected in the behavior of the temperature dependence of the potential part of the specific internal energy, which is used to identify the crystallization temperature. Furthermore, it was found that the values of the specific internal energies (per atom) are in good agreement.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):399-410
399-410
On the thermal stability of icosahedral metallic nanoclusters: molecular dynamics simulations
Abstract
Using molecular dynamics modeling and the embedded atom method, the thermal stability of icosahedral magic nanoclusters of Ag, Au, Cu, Ni, Pd, and Pt face-centered cubic metals was studied, i.e. the stability of their characteristic structure, which relates to the preservation or destruction of their shell structure and symmetry associated with the presence of six symmetry axes of the fifth order, in particular, in the process of heating from 10 K to a temperature exceeding their melting point. It has been established that up to the beginning of melting, icosahedral nanoclusters with the number of atoms 13, 55, 147, 309, and 561 retain their characteristic symmetry, i.e. they do not transform into isomers of other types. This behavior during heating differs significantly from the behavior of cuboctohedral (face-centered cubic structure) nanoclusters, the melting of which is preceded by their transition to icosahedral isomers. At the same time, the behavior of the caloric curves, i.e., the temperature dependences of the potential part of the specific internal energy (cohesive energy) of icosahedral nanoclusters of different metals is markedly different. In particular, the melting of icosahedral Ag and Ni nanoclusters is accompanied by pronounced jumps in this dependence. Accordingly, this transition can be interpreted as a phase transition of the first order and the corresponding temperature as the melting point. For Cu and Pd icosahedral nanoclusters, the corresponding jumps are less pronounced, and the melting of Au and Pt nanoclusters is not accompanied by jumps in the caloric curve.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):411-418
411-418
Comparative description of binding thermodynamic parameters of perfluorinated alkanes with polyaromatic hydrocarbons. The quantum chemical approach
Abstract
The paper presents a comparative analysis of the binding thermodynamic parameters for CnH2n+2 alkanes and their perfluorinated analogues CnF2n+2 (n = 2-14) with a graphene-like surface. The model structures of the graphene surface are performed by polyaromatic hydrocarbons of the coronene series: coronene and tricircumcoronene. The calculations are done using the quantum chemical semiempirical PM6-DH2 method, and supplemented by the results of density functional theory calculations using hybrid functionals B3LYP/6-311G** and wB97X-D4/cc-pVDZ. It has been shown that the binding of perfluorinated alkanes to a graphene surface is more energetically advantageous than conventional alkanes, which is consistent with the few experimental data on the isosteric heat of adsorption of regarded compounds. Thus, the contributions of the intermolecular C–H∙∙∙π and C–F∙∙∙π interactions to the binding enthalpy are almost identical. However, in terms of the entropy factor, these interactions differ by about two times in favor of the C–F∙∙∙π interactions. As a result, the latter ones turn out to be about 60% more energetically preferable than the C–H∙∙∙π analogues according to the binding Gibbs energy criterion.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):419-432
419-432
Determination of θ-conditions for the parameterization of the intrachain stiffness of a linear polymer chain in the dissipative particle dynamic method
Abstract
To construct mesoscale models of molecular systems, the structure of all chemical components is simplified through a transformation known as «coarsening». In the case of modeling polymer materials, the conformational properties of roughened polymer chain models may not correspond to the original chemical prototypes. This can be compensated by introducing additional potentials into the model. Conditions for a model of a linear polymer chain with «beads and springs» in the infinitely diluted solution are determined using the dissipative particle dynamic method. It has been shown that the maximum amplitude value of the conservative force, that determines the interaction between the polymer and the solvent corresponding to these conditions, strongly depends on the stiffness constant Kb of the bond deformation potential. When Kb is greater than 30, this value tends to saturate. For Kb = 200, a relationship between the characteristic ratio of model chain lengths and the stiffness constant Ka was calculated. The results obtained are in good agreement with literature data and can be reproduced using theoretical calculations. The functional relationship between C∞ and Ka is universal and can be applied to construct accurate models of various polymers when their conformational characteristics are important.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):433-446
433-446
Adsorption of a magnesium monolayer on the GaN(0001) surface
Abstract
The density functional method was used to calculate the adsorption of a monolayer of Mg atoms on the surface of the (0001) GaN face. The 2D layer GaN was modeled by a GaN(0001) 2×2 supercell containing 10 GaN bilayers. The GaN surface has a metallic character, which is ensured by the presence of a zone of surface states near the Fermi level. The electron density of states and the adsorption energy of Mg atoms were calculated for three stable sites of Mg atom adsorption: on the surface Ga or N atoms and when 2 Mg atoms are adsorbed on N atoms and 2 Mg atoms are adsorbed in the bridging position between N atoms. Adsorption of Mg atoms is preferable in the last position. One Mg atom accounted for 1 surface Ga atom in the first GaN bilayer. The adsorption energy of Mg is 1,175 eV. Adsorption of Mg atoms results in minor reconstruction of the GaN surface: the maximum shift of the Ga (N) atom layer does not exceed 0,035 Å. Adsorption of Mg results in the formation of a wide surface zone below the Fermi level. The bond with the GaN(0001) surface is achieved by the formation of a bond between the valence electrons of magnesium and the valence electrons of the GaN substrate.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):447-454
447-454
Evaluation of specific surface energy of Ag nanoparticles based on molecular dynamics results
Abstract
After analyzing the problem of extending the Gibbs surface excess method to nanoscale objects, applying the Gibbs method to evaluation of the specific surface energy of metallic nanoparticles is considered. The proposed approach, which we have exemplified on spherical Ag nanoparticles and nanodroplets, is based on the use of molecular dynamics results for the temperature and size dependencies of the potential term into the specific (per atom) internal energy. The calculations were performed for the equimolecular dividing surface. In this case, the excess surface energy was determined relative to the bulk mother phase (comparison phase), which was chosen to be the solid fcc phase of the same metal at the same temperature as the small object under consideration. The obtained values of the specific surface energy depend on temperature and are consistent with the experimental values for the corresponding bulk comparison phases. At the same time, a noticeable change (decrease) in the specific surface energy occurred only when the solid-liquid phase transition took place.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):455-465
455-465
Structural transformations in quaternary nanoalloys Cu-Au-Pt-Pd of different morphology under successive thermally induced cycles
Abstract
A molecular dynamics study of the structure formation processes in four-component Cu-Au-Pt-Pd nanoparticles (with a total number of 4000 atoms) was carried out during two successive cycles of thermally induced action. Two scenarios were proposed: the first scenario — both cycles with the same rate of 0,25 K/ps; the second scenario – the first cycle with a rate of 1 K/ps, the second – 0,25 K/ps. Six types of initial configurations for the Cu-Au-Pt-Pd nanosystem are considered: uniform distribution of atoms (Pd2400-Pt800-Au600-Cu200), core-shell configurations in which palladium atoms act as a shell, while the remaining elements are uniformly distributed in the core ((Cu200-Au600-Pt800)@Pd2400) or represent an onion-like structure (Cu200@Au600@Pt800@Pd2400), as well as Janus structures of three configurations: Cu200/Au600/Pt800/Pd2400, Cu100/Au300/Pt400/Pd2400/Pt400/Au300/Cu100, and Pd1200/Pt400/Au300/Cu200/Au300/Pt400/Pd1200. For each of the presented systems, caloric dependences of the potential part of the specific internal energy corresponding to the heating and cooling processes (for two cycles) were obtained; the hysteresis parameters of the melting and crystallization temperatures were determined, the patterns of chemical and structural segregation for configurations corresponding to the end of cooling were described. For the Au and Pd components, their distributions in the considered Cu-Au-Pt-Pd nanoparticles were constructed and analyzed. The specific surface energy, the value of which determines the mechanical stability, was also estimated. The results obtained for the specific surface energy were compared with the available experimental data taking into account the size effect.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):466-484
466-484
Metallic nanostars as a new object for atomistic simulation
Abstract
The thermal stability of gold nanostars with two types of initial morphology: a great dodecicosacron and a great inverted snub icosidodecahedron was studied. The initial nanostar configurations were obtained using the Atomsk program, followed by structural relaxation. Thermally induced stress was simulated using the Monte Carlo method (Metropolis scheme). Interatomic interactions were described by the tight-binding potential. Critical destabilization temperatures, which increase with increasing size for both types of the initial morphology, were determined. Patterns of structural segregation during thermally induced stress up to the melting temperature were also established. Despite the dominance of the local FCC structure in the central part of the nanostars, the nature of the distribution of local HCP structure differs for the considered types of the initial morphology up to the melting temperature. Thermal degradation was shown to begin with «multiple rays» of nanostars, where the local atomic density is lower than the surface average one. The results allow us to predict the stability of anisotropic nanoparticles for photothermal applications.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):485-496
485-496
Study of magnetic properties of cobalt nanofilms under external field conditions using mathematical modeling
Abstract
In this paper, we study the magnetic characteristics of cobalt nanofilms. Cobalt films are of interest for integration into hybrid systems, which opens up new possibilities for the development of multifunctional devices. The aim of the study is to model the magnetic characteristics of cobalt nanofilms with different thicknesses under the influence of various magnetic fields. To achieve this goal, a mathematical model was used that describes the motion of atoms and the reorientation of their spins. The model is based on the Langevin and Landau-Lifshitz-Gilbert equations for describing the system dynamics. The results of the study show the influence of the external magnetic field on the magnetic characteristics of cobalt films with a thickness of 1,8 to 7,1 nm. With an increase in the film thickness, a decrease in the magnetization modulus is observed. The value of the magnetization modulus of the system shows a nonlinear dependence on both the number of crystalline cobalt layers and the magnitude of the external magnetic field. At different values of magnetic induction, changes in the behavior of magnetization are recorded, including the formation of domains and domain walls. The developed model allows analyzing the influence of various factors on the magnetic properties of materials, which can contribute to the optimization of thin-film structures for use in spintronics. The study emphasizes the importance of understanding the magnetic properties of thin films for the development of new technologies in this area.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):497-505
497-505
Initial stage of the coalescence process exemplifying on Ag nanoparticles
Abstract
Understanding the formation and evolution of metal nanoparticle arrays is a very important task, as they are increasingly used in various technical devices. The size and shape of nanoparticles, as well as the distance between them, have a great influence on their properties. Coalescence is one of the main processes that are responsible for changing these geometric parameters of the nanoparticle array. In the case of metal nanoparticles, it was found that their aggregation depends on their mutual crystalline orientation, resulting in various mechanisms of association. The influence of the crystalline orientation of nanoparticles on the coalescence mechanism was confirmed by molecular dynamics simulations. The coalescence of silver nanoparticles of various diameters was studied; the distance between the particles varied from 0,5 to 1,5 nm, and the simulation time corresponded to 200 ps. The actual appearance and structure of the studied nanoparticles were determined using OVITO and XMakemol visualizers. Analysis of the results showed that, in the case of silver nanoparticles, coalescence in most cases occurs by the oriented attachment growth mechanism.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):506-513
506-513
The electronic structure of free radical 9-fluorenyl within the framework of QTAIM
Abstract
The paper presents the results of studying the influence of free valence on the electronic structure of 9-fuorenyl radical in comparison with the fluorene molecule. The geometric structure and electron density distributions in the above compounds were calculated using the density functional method B3LYP/6-311++G(3df,3pd) 6d 10f. The electronic structure of the studied compounds was investigated within the framework of the «quantum theory of atoms in a molecule». The total electron density of the compounds under consideration was divided into spatial areas («topological» atoms) combined for analysis into atomic groups. Their electronic parameters were calculated: charge, volume, and spin density (for radicals). A comparative analysis of the parameters of atomic groups in the molecule and radical was performed. The characteristics of bond critical points and cycle critical points were obtained and analyzed. The concepts of «radical center» and «free valence» are quantitatively characterized, and the conjugation of free valence in 9-fluorenyl is shown through the distribution of spin density.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):514-521
514-521
Comparative molecular dynamics simulation of coalescence and sintering in Au-Au and Si-Si systems
Abstract
Comparative molecular dynamics modeling of coalescence and sintering of Au nanoparticles containing each 1000 atoms and Si nanoparticles also containing 1000 atoms was performed using the LAMMPS program. Interatomic interaction in the Au1000-Au1000 system was reproduced using the embedded atom method, and in the Si1000-Si1000 system – using the Stillinger-Weber potential. During the simulation of the Au1000-Au1000 system, the temperature was uniformly increased from 200 K to 1500 K, and, during the simulation of the Si1000-Si1000 system, from 300 K to 2200 K. Until the melting temperature of nanoparticles of the selected size was reached (900 K for Au nanoparticles and 1450 K for Si nanoparticles, respectively), the evolution scenarios for these systems corresponded to the isothermal low-temperature sintering, and upon reaching the melting temperature, to coalescence of nanodroplets. The temperature and kinetic dependences of the following quantitative characteristics of the coalescence and sintering processes were found and analyzed: the potential part of the specific internal energy, the degree of sintering (shrinkage coefficient), the radii of gyration of both the system of two nanoparticles and the atomic subsystems corresponding to atoms of individual nanoparticles. It has been established that despite significant differences in the chemical bonding nature in the Au1000-Au1000 and Si1000-Si1000 systems (metallic and covalent bonds, respectively), sintering of Au and Si nanoparticles is characterized by the same patterns.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):522-536
522-536
Effect of defect concentration in perovskite and heterojunctions on photovoltaic characteristics of a solar
Abstract
Increasing the stability and reliability of perovskite solar-to-electric energy converters is one of important issues in the field of green energy. In this regard, a new model of the solar cell structure is proposed that is capable of stabilizing photoelectric characteristics at a level approaching the theoretical limit for a single-layer perovskite. The influence of defect concentration on the characteristics of solar energy conversion into electrical energy in perovskite solar cells in the ITO/ZnO/CH3NH3PbI3/NiO/Ag structure model is considered. Numerical calculations performed show a significant dependence of the solar cell characteristics on the defect density at the layer boundaries and in the perovskite absorber itself. The dependences of the photoelectric efficiency characteristics of the solar cell on the defect density at the oxide heterojunctions with the absorber and the absorber itself are established. In the studied structure, the limit values of defect concentration were established, below which the maximum values of open-circuit voltage, short-circuit current density, photoelectric efficiency, and efficiency are achieved. The concentration of defects at the CH3NH3PbI3/NiO interphase boundary has virtually no effect on their values. A volt-ampere characteristic has been constructed for the proposed model and optimal photoelectric characteristics have been calculated.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):537-543
537-543
Influence of the structural factor on the tribological characteristics of titanium alloy obtained by selective electron beam melting
Abstract
The article is devoted to an experimental study of the influence of microstructure features of the Ti – 6Al – 4V alloy obtained by electron beam melting technology on the tribological properties: hardness; friction coefficient; abrasive wear resistance. The microstructure of the alloy consists of colonies α′-plates 1,5-2 μm thick and interlayers of the β-phase 0,2 μm in size. Hardness was measured at low loads N = 1-2 N (microhardness) and at loads N = 90–180 N (indentation hardness). The friction coefficient was determined on a microtribometer according to the ball-plane scheme in a pair with a steel indenter at loads of 2-5 mN. Wear resistance was studied by friction against a fixed abrasive according to the ball-plane scheme. The microstructure and properties of the samples were studied in two mutually perpendicular planes: in the layer and in the direction of synthesis. Anisotropy of microhardness and friction coefficient under low loads was revealed. In the layer plane, the microhardness under loads of several newtons is 900-1000 MPa lower than on the lateral surface of the sample. Under low contact loads, the friction coefficient in the contact of a spherical steel sample with a flat layer surface is approximately 20% lower than in the contact of the same steel sample with the lateral surface of a titanium alloy sample. With increasing contact load, the difference in properties disappears. Abrasive wear resistance in the direction of sample synthesis is 30% higher than in the layer plane, which is explained by the role of the structural factor. It is shown that the orientation of the colonies of α′-plates has a decisive effect on the tribological properties.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):544-553
544-553
Synthesis of a composite sorbent based on hydroxyapatite and zeolite and its sorption properties
Abstract
The work is devoted to the study of sorption properties of a new composite sorbent based on synthetic zeolite and hydroxyapatite obtained by the sol-gel method as a sorbent for ions of heavy non-ferrous metals (chromium, nickel, iron, copper and zinc) from acidic aqueous solutions. The chemical qualitative and quantitative composition, morphology of the initial reagents, and the obtained solutions were studied. It was found that the composite sorbent has a high specific surface area (1600 m2/g) and exhibits high sorption activity and sorption capacity, higher than monosorbents of synthetic zeolite and hydroxyapatite, and also higher than that of a mechanical mixture of hydroxyapatite and zeolite. The characteristics of the composite sorbent were determined by IR spectroscopy, the presence of uncharacteristic absorption bands of 907 and 873 cm-1 in the spectrum was shown, which indicates the formation of new chemical bonds. The phase composition of the composite sorbent was determined by X-ray phase analysis, and the morphology was studied by scanning electron microscopy. The high sorption activity and capacity of the resulting composite sorbent can be used for additional purification of wastewater from enterprises, which can be implemented in a number of industrial productions. Based on the results of the study, an application for a patent was filed.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):554-562
554-562
The effect of the synthesis method on the strength characteristics of ceramics based on fluorapatite
Abstract
The article discusses the possibility of obtaining hardened bioceramics based on fluorapatite. Composite materials were obtained in two ways. In the first case, by mechanical synthesis of nanostructured hydroxyapatite obtained by precipitation from a solution with an estimated amount of doping components (calcium fluoride, nonstoichiometric titanium oxide, or zirconium dioxide) and subsequent high-temperature treatment. In the second case, the mechanochemical reinforcement was carried out with the direct introduction of a reinforcing component (non-micrometeometric titanium oxide or dicyrconium) into ultrafine fluorapatite obtained by precipitation from solution. The synthesized samples are certified using modern physico-chemical analysis methods. The influence of the qualitative and quantitative composition of the composite on the sintering processes and the strength characteristics of the studied samples is shown. It has been experimentally established that materials meeting the required functional characteristics can be obtained by hardening fluorapatite with zirconium dioxide in an amount of 5 wt.% as well as due to the joint reinforcement of hydroxyapatite with calcium fluoride and titanium oxide in equal amounts (15 wt.%). Composite materials of the specified composition are thermally stable, have a constant phase composition, a dense uniform structure with a high degree of crystallinity with developed porosity, and are a promising material for further research with a view to introduction into medical practice.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):563-576
563-576
Nanodispersed magnetic oil: relationship between liquid phase composition and tribological characteristics
Abstract
The use of nanodispersed magnetic oil for lubricating plain bearings of modern high-tech equipment allows to increase its durability and performance. The paper assesses the effect of the dispersion medium, nanodispersed magnetic phase, antiwear additives and fillers on the tribological properties of magnetic oil. Three-component magnetic lubricating oils with different dispersion medium compositions were studied. Synthetic organosilicon fluids belonging to different groups were used as dispersion medium. Magnetic oils stabilized by using organosilicon acids, ionogenic surfactants, fatty acids, etc. were tested. According to the results of tribological tests, it was found that in a wide range of friction conditions, the lubricating properties of nanodispersed magnetic oil are higher, the higher these properties are in the dispersed medium. The effect of surfactants stabilizing the colloidal structure of nanooils on the corrosion-mechanical component of wear was studied. A conclusion has been made about some advantage of oils with polymer shells on particles. A method has been proposed for removing agglomerates of ferroparticles formed during the synthesis of lubricant and as a result of particle flocculation under the action of magnetic forces, by the action of a force non-uniform magnetic field. The need to continue research in this direction has been shown.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):577-584
577-584
Some features of the influence of nanodispersed magnetic lubricating oil on friction and wear of structural components
Abstract
For friction units operated under conditions of no maintenance, with a significantly limited lubrication zone, one of the optimal solutions is the use of nanodispersed magnetic lubricating oils. The effect of the structural components of nanodispersed magnetic lubricating oil: magnetic phase, solid lubricant phase, antiwear additives on its tribological properties was studied. The presence of an optimal concentration of ferromagnetic nanoparticles during wear of surfaces with relatively low microhardness was established. This is due to a change in processes in the friction zone: the hardening effect is replaced by abrasive wear. For hard surfaces, wear is predominantly abrasive. Considering the importance of retaining the lubricating film of magnetic oil in the contact zone, the behavior of ferromagnetic nanoparticles in a gradient magnetic field was analyzed. Redistribution of particles in the force field and an increase in the number of particles near the surface of the sample under study were established. This leads to an increase in the rate of formation of a lubricating film on the friction surface and a decrease in the friction force by 10-15% for relatively low sliding speeds of surfaces. Evaluation of the effect of the studied additives on the structure and physical and mechanical properties of magnetic nanooils showed a complex nature of changes in their properties during full-scale tests. To improve the antifriction characteristics of magnetic oils, it is necessary to use 3-4 times more additives than traditional oil. It was found that the tested solid lubricant fillers have a positive effect on the friction properties of the magnetic tribological unit, but their amount should be significantly limited to avoid loss of controllability of the magnetic field.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):585-597
585-597
Clustering of phase-change material Ge2Sb2Te5 nanoparticles obtained by laser-induced forward transfer techniques
Abstract
The paper presents experimental results on the synthesis of nanoparticles of phase-change Ge2Sb2Te5 material by direct laser-induced transfer. Thin films obtained by thermal vacuum deposition were used as a donor material, and silicon wafers were used as acceptors. The laser-induced transfer was carried out by pulsed laser radiation of the sub-nanosecond duration. The morphology, topology, and sizes of the obtained nanoparticles were analyzed using scanning electron microscopy. The clustering features were analyzed based on the Langevin equation. It is demonstrated that the temperature regime during laser transfer has the greatest effect on the cluster formation, which is explained by the fact that the crystalline phases of the studied material are high-temperature. The results of the work show the possibility of creating an element based on nanoparticles with a certain distribution and size, as a technological alternative to devices based on thin films. The use of nanoparticles will allow for energy efficiency, greater flexibility and smooth switching, as well as enable neuromorphic and stochastic computing. Controlled clustering will allow you to create switchable elements with specific properties that may not be available when using thin film-based architectures.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):598-605
598-605
Technologies and development prospects of ferroelectric memory devices
Abstract
Ferroelectric memory is one of the most promising types of non-volatile solid-state memory due to its high speed, low power consumption and resistance to external influences. Its operating principle is based on the ability of ferroelectric materials to maintain the polarization direction after removing the external voltage. The paper considers the physical principles of this type of memory, the features of the 1T, 1T-1C, 2T-2C, and chain-FRAM cell architectures. Particular attention is paid to the problem of destructive reading, typical for most ferroelectric structures, and modern methods for solving it: acoustic, pyroelectric, photoelectric and electro-optical interrogation methods. In addition, an analysis is made of both the scaling limitations associated with the use of traditional ferroelectric materials, such as lead zirconate titanate, and the search for alternative materials including hafnium oxide, which provides stable polarization at a thickness up to 10 nm. A review of technological solutions aimed at improving the scalability and reliability of ferroelectric memory in the context of modern requirements for microelectronics is conducted.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):606-614
606-614
Analysis of plasmonic properties of Ag nanoparticles
Abstract
In the presented work, some features of the use of metal nanoparticles in plasmonics, as well as methods for their synthesis, are studied. An assessment of experimental data on the possible improvement of technical characteristics of light-emitting diodes (LED, QLED, OLED) allows us to say that one of these ways will be the inclusion of metal nanoparticles in the active layer for use in surface plasmon resonance. However, the intensity of such resonance depends on many factors, the main ones being the shape and size of the plasmonic nanoparticle. Traditional materials here are Ag, Au, and Cu, but since recently it was possible to achieve stable synthesis of a wide range of nanostructures only for Au and Ag, these chemical elements and, possibly, alloys based on them, are the most promising materials for use in plasmonics. Based on the analysis, it was concluded that by controlling the size, shape, chemical composition, and internal structure of Ag nanoparticles, light can be effectively controlled with unprecedented accuracy, and, therefore, determining these characteristics of individual metal Ag nanoparticles is of great interest for studying their possible optical response.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):615-626
615-626
Formation of solid solutions and composites in the system ZnO-ZrO2
Abstract
It is proposed to obtain solid solutions and composites based on zinc and zirconium oxide systems as promising photoactive materials. The synthesis method involves the use of a precursor technology. Partially zinc-substituted zirconyl formates were previously obtained as precursors. It is shown that thermolysis of precursors in air at 700°C stabilizes Zn1-xZrxO1+2x solid solutions with a wurtzite structure in the range 0≤x≤0,06. Increasing the zirconium concentration leads to the formation of hybrid materials of the core/shell type Zn1-xZrxO1+2x/Zr1-xZnxO2-x, consisting of solid solutions of two types. For Zn1-xZrxO1+2x (0≤x≤0,8), the wurtzite structure is retained. In the Zr1-xZnxO2-x system, a composite based on the tetragonal phase t-ZrO2 is stabilized. In the homogeneity region of Zr1-xZnxO2-x at 0,1≤x≤0,3, single-phase solid solutions also have a tetragonal modification t-ZrO2. Zirconium doping of ZnO promotes accumulation of negative charge on the surface of oxide material particles, which is associated with adsorption of hydroxide ions from alkaline solutions. When doping ZrO2 by zinc, a general tendency to stabilization of the surface charge in Zr1-xZnxO2-x solid solutions is observed. In this case, a shift in the ζ-potential values of dispersions to the region of positive values is observed when moving from solid solutions to hybrid materials t-Zr1-xZnxO2-x/Zn1-xZrxO1+2x, which will promote sedimentation of objects when extracting them from the photoreactor zone.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):627-635
627-635
Advanced methods for growth thin films of GaAs1-x-yNxBiy: a review
Abstract
This review summarizes the latest advances in the fabrication of thin films of GaAs1-x-yNxBiy solid solutions for potential applications in optoelectronics. It is demonstrated that GaAs1-x-yNxBiy thin films can be produced using molecular beam epitaxy, metal-organic vapor phase epitaxy, and pulsed laser deposition. However, the process remains technically challenging primarily due to the numerous parameters that influence the structural properties of the films. The highest concentrations achieved were 4,7% bismuth and 2% nitrogen in epitaxial thin films grown by molecular beam epitaxy. The bismuth content decreases linearly with increasing the substrate temperature up to 410°C, assuming a constant excess flux of bismuth atoms. Notably, at 350°C, it was possible to grow thin films without the bismuth droplet formation on the surface. Additionally, it has been shown that CuPt-type ordering can occur in GaAs1-x-yNxBiy alloys. This ordering could enable control over the local atomic environment of bismuth and nitrogen atoms through long-range chemical ordering. For high-quality GaAs0,964N0,018Bi0,018 films grown at 450°C via metal-organic vapor phase epitaxy, a decrease in band gap energy of approximately 141 meV/% N was observed as the nitrogen concentration increased. While pulsed laser deposition currently produces polycrystalline films with relatively low nitrogen content, it holds significant potential for further development and optimization in this field.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):636-648
636-648
Morphology and conductivity control in hexagonal ZnO nanorods through annealing for gas sensor applications
Abstract
This study investigates the influence of the annealing temperature (300-500°C) on the electrophysical properties of nanostructured zinc oxide (ZnO) layers synthesized by a sol–gel method. The obtained samples consist of an ensemble of hexagonal nanorods. Quantitative morphological analysis revealed that the kinetics of the nanorods growth in the temperature range of 300-450°C follows an Arrhenius-type dependence with the activation energy of 0,35 eV, which corresponds to a surface diffusion-controlled mechanism. Experimental data demonstrate a non-monotonic relationship between the conductivity and annealing temperature, with a distinct minimum observed between 350°C and 400°C. It was found that annealing at 400°C for five hours results in stabilization of the electronic properties, yielding a minimal conductivity drift of 0,19 %/h. The observed effect is attributed to a competition between two processes: a decrease in the concentration of bulk donors (oxygen vacancies and zinc interstitials) and an increase in the average crystallite size with rising the annealing temperature, leading to the formation of shunting conductive channels. The dependence of the steady-state conductivity of the ZnO sample in dry air on the annealing temperature, as calculated using a flat-band model, satisfactorily describes the experimental data. The obtained results open prospects for the targeted synthesis of highly sensitive and stable sensing elements for chemical resistive gas sensors based on ZnO.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):649-657
649-657
Investigation of the structural formation patterns in five-component Ni-Cu-Fe-Co-Cr nanosystems: atomistic simulation and experiment
Abstract
In this work, the structural and thermodynamic characteristics of five-component nanoparticles with equiatomic and stoichiometric compositions, various component distributions, and initial sizes of 5,8-8,5 nm were investigated. Molecular dynamics simulations were performed using the LAMMPS and MDSym software packages. The dependencies of the melting and crystallization temperatures on the nanoparticle size were obtained, revealing a pronounced size effect. It was shown that equiatomic nanoparticles exhibit the copper surface segregation (up to 65%), while for stoichiometric nanoparticles this value reaches up to 75%. Data on the specifics of the phase composition were obtained: for equiatomic nanoparticles, a local FCC structure with HCP-type defects predominated, while for stoichiometric nanoparticles, the formation of five-grained defective structures was observed. The simulation results (radial density distributions) were compared with experimental data on nanoparticles obtained by the method of electric explosion of wires, which confirmed individual results on the distribution of components in the volume of the nanoparticle and by the patterns of the surface segregation.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):658-673
658-673
Structure of quaternary Ni-Cu-Fe-Co nanoalloys under thermally induced effect: atomistic simulation
Abstract
A comprehensive study of equiatomic four-component Ni-Cu-Fe-Co nanoparticles of 5 nm in size was conducted. Simulations were performed using molecular dynamics simulations and the tight-binding potential. This nanosystem was found to be highly stable: crystallization occurred in all cases with the formation of a predominantly local FCC structure alternating with a local hcp structure. At cooling rates above 0,5 K/ps, the proportion of the local FCC structure decreased by 5% due to an increase in local HCP surroundings and the appearance of local inclusions of a BCC environment. The volume fraction of the BCC lattice did not exceed 2%. The nanosystems under study are shown to be prone to the formation of hierarchical, labyrinthine structures with pronounced copper segregation on the surface. Thus, it was established that equiatomic quaternary Ni-Cu-Fe-Co nanoparticles are characterized by the formation of a copper shell with inclusions of cobalt and iron.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):674-686
674-686
Corrosion resistance of composite zinc-nanodiamond coatings
Abstract
In the work, nanodiamonds were obtained by the method of hydrodynamic cavitation by LLC ICC «Sintez». The synthesized nanodiamonds were studied using atomic force microscopy and it was found that their particles have a shape close to spherical, and the particle size along the Z axis does not exceed 10 nm. The particles agglomerate and form larger structures up to 100 nm in size. The synthesized nanodiamonds in the form of colloidal solutions with a concentration of 0,5%, 1%, 3%, 5% and 7% were used in a galvanizing electrolyte to obtain composite zinc-nanodiamond coatings. The resulting coatings were studied using X-ray phase analysis and scanning electron microscopy. The presence of a carbon phase in the composition of the composite zinc coating corresponding to a diamond-like structure was proven. It was found that the morphological features of the zinc-nanodiamond coating surface differ significantly from the morphology of the zinc coating surface, which is expressed in the absence of a large number of depressions and irregularities. The corrosion activity of zinc-nanodiamond coatings was tested in a 3% sodium chloride (NaCl) solution. It was determined that composite zinc-nanodiamond coatings have increased corrosion resistance compared to zinc coatings, while the corrosion rate is reduced by 42%.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):687-695
687-695
Metal oxide nanocomposites with plasmonic nanoparticles for photocatalysts and gas sensors
Abstract
The increased absorption of light by metal oxide materials modified with plasmonic nanoparticles in the visible range makes them excellent candidates for use in photocatalysts and light activated gas sensors. The photocatalytic properties of these nanocomposite materials are studied. The main results of research on the decomposition of various organic dyes using these catalysts are analyzed. The effect of metallic nanoparticles on photocatalytic properties is explained by the formation of a Schottky barrier, as well as the effect of localized surface plasmon resonance (LPPR). The Schottky barrier at the metal-oxide interface efficiently separates and transfers charge carriers through an internal electric field, leading to an increase in photodegradation efficiency. This is achieved by separating electron-hole pairs and reducing the rate of charge carrier recombination. Due to the LPPR, the absorption of light increases, which leads to an increase in the generation of active charge carriers. Various authors have studied the response of composite structures composed of metal oxides and plasmonic nanoparticles to oxidizing and reducing gases under different experimental conditions, and their results have been summarized. The main reason for this increased response is an increase in the concentration of adsorbed oxygen ions due to transfer of photogenerated in plasmonic nanoparticles electrons. Mechanisms of the influence of the surface plasmon resonance effect on the properties of chemical gas sensors and photocatalysts involves the formation of a Schottky barrier when a noble metal contacts a semiconductor, the direct transfer of electrons, a local amplification of the electric field, and the transfer of the plasmon resonance energy.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):696-711
696-711
Template effect in the synthesis of micro- and nanoscale oxide materials and compositions based on them in combustion reactions of glycine-nitrate precursors
Abstract
It is evident from the extant results of experimental studies that the possibility of the manifestation of the template effect in the formation of anisometric micro- and nanoscale formations in oxide and composite systems has been analysed. In the synthesis of micro- and nanoscale oxide (complex-oxide) materials, compositions based on them, such as metal-oxide, in the combustion reactions of glycine-nitrate precursors, the template effect is observed, which promotes the formation of anisometric (extended) particles and their ensembles. In addition to the established facts documented in the extant literature, the occurrence of the aforementioned morphology (i.e. the synthesis of hydroxides and oxides of lanthanum, neodymium, praseodymium, holmium, samarium, yttrium, gadolinium, erbium and europium) has been observed in systems involving the synthesis of magnetic particles (e.g. strontium hexaferrite) and in other non-magnetic materials. In the process of synthesising magnetic complex oxides, this effect is instrumental in the production of high coercivity materials. The aforementioned effect is also applicable to samples of bactericidal composition of aluminium oxide with silver nanoparticles obtained in combustion reactions. The formation of anisotropic formations may be attributed to the presence of glycine, whose amphoteric molecules, in their zwitterion form, possess the capacity to establish ordered spatial structures that function as templates for the synthesis of target phases in combustion reactions.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):712-719
712-719
Strengthening mechanisms in metal-graphene nanocomposites: the role of interfaces and amorphous matrix
Abstract
Current studies of metal-graphene (G) nanocomposites (such as Al/G, Ni/G, Ti/G) demonstrate their outstanding mechanical properties when combining an amorphous metal matrix with dispersed graphene. Analysis of the literature data allows us to identify two key factors responsible for the increased strength and thermal stability of such materials: (i) the formation of hybridized metal-carbon bonds at the phase interface and (ii) special deformation mechanisms, including the activity of shear transformation zones and dislocation locking at the interfaces. For amorphous alloys, the free volume plays a decisive role, promoting local restructuring and the formation of strengthening nano phases. Comparative analysis of molecular dynamics modeling data and experimental results shows their good consistency, which confirms the effectiveness of graphene as a reinforcing phase. The obtained results allow us to consider metal-graphene nanocomposites as a promising direction in the development of new materials with improved mechanical and thermal characteristics, including providing exploitation in extreme conditions.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):720-732
720-732
Polyoxotungstometalates of 3d metals in the synthesis of hybrid carbon-mineral nanomaterials by the CVD method
Abstract
This paper presents the results of an assessment of the possibility of obtaining hybrid carbon-mineral nanomaterials by the method of catalytic chemical deposition of carbon from the gas phase using complexes of polyoxotungstometalates with 3d-metals of the general formula (NH4)X[PW11O39Me(L)]×nH2O, where Ме – Fe, Co, Ni, Cu; L – H2O, C6H12N4 (hexamethylenetetramine), as components of metal oxide catalysts for the growth of carbon nanotubes, which are a source of reduced metal particles active in the catalytic process. The synthesis products were studied by transmission electron microscopy and X-ray phase analysis. It has been established that even at a very low molar metal-carrier ratio (0,03÷1), a catalytic process is realized with the formation of carbon nanotubes. It is shown that, regardless of the qualitative composition of the catalyst, there is also an accumulation of the product of the non–catalytic flow, nanocarbon, which forms a hybrid supramolecular carbon-carbon complex in the form of lateral deposits of graphene-like carbon on the outer surface of carbon nanotubes. According to X-ray phase analysis of isolated and purified synthesis products using structurally different polyoxotungstometalates, X-ray diffractograms show reflexes at the same angular positions, which makes it possible to assume the formation of two types of hybrid carbon-mineral nanomaterials: carbon nanotubes-nanocarbon-tungsten oxides and nanocarbon-tungsten oxides.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):733-741
733-741
Perovskite quantum dots doped with neodymium ions: synthesis and optical properties
Abstract
The work presents a synthesis method, structural and optical characteristics as well as a comparative analysis of properties of colloidal quantum dots based on halide perovskites doped with Nd³⁺ ions with 20% substitution of lead ions. Nanocrystals with a controlled content of a rare-earth element were synthesized by a hot injection method, which ensured the production of stable colloidal structures with a specified level of doping. The structural analysis using an auto-emission scanning electron microscope confirmed the polycrystalline nature of the nanoparticles with the grain size of ~30 to 200 nm. The elemental composition corresponds to the initial materials, which indicates the controllability of the doping process. The quantum yield of photoluminescence was 40%, which is a high value for Nd-doped perovskite systems. The emission spectrum with a maximum at 458 nm shows a pronounced blue shift due to the effect of Nd³⁺ on the band gap. Diluted dispersions are recommended to obtain reliable spectral data. The obtained results confirm the effectiveness of the proposed approach and open up prospects for the application of doped perovskite nanocrystals in optoelectronics, photonics, and scintillation technologies.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):742-751
742-751
Study of the possibility of autoclave production of ultrafine hydroxyapatite. Assessment of the effect of technological parameters on the composition of the final product
Abstract
The article discusses a technologically simple method for the autoclave production of ultrafine hydroxyapatite, suitable for the manufacture of pharmaceutical compositions, medicines and preparations. A thermodynamic assessment of the possibility of the reaction depending on the ratio of the initial components and technological modes was carried out. The temperature range, the feed rate of the phosphoric acid solution, the optimal concentrations of the initial components, their stoichiometric ratio, which ensures a high yield of the final product and its degree of purity, have been experimentally established. The synthesis products are certified using state-of-the-art physico-chemical analysis methods. The composition of the final product was monitored by X-ray phase analysis, differential thermal analysis, the surface morphology of the synthesized products was evaluated by scanning electron microscopy, and the surface characteristics by the Brunauer-Emmett-Teller method. A patent has been obtained for a simple technological method developed as a result of the work for the production of amorphous hydroxyapatite with a high degree of purity.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):752-763
752-763
Metal oxide nanocomposites with plasmonic nanoparticles: synthesis and diagnostics
Abstract
Plasmonic nanostructures based on metal oxides modified with noble metal nanoparticles have been attracting increasing attention among researchers working in fields such as photodynamic therapy, biosensors, photonics, optoelectronics, surface-enhanced Raman spectroscopy, and catalysis. The characteristics of these nanocomposites depend on the size of nanoparticles and are determined by the methods and conditions used for their synthesis. In this paper, approaches to the synthesis of «plasmonic nanoparticles – metal oxide» nanocomposites – are analyzed. Methods for producing metal nanoparticles on the surface of pre-synthesized metal oxides are considered, including various methods of precipitation from the gas and solution phases. A group of methods for the single-stage synthesis of nanocomposites is identified, which includes variations of the sol-gel method and others. The particle size, particle size distribution, and uniformity of the arrangement of metal nanoparticles in the formed nanocomposites are analyzed. The possibilities of controlling the interaction of components in nanocomposites are shown by using diffuse reflection spectroscopy by the appearance of absorption bands corresponding to plasmon effects. The interaction of components leads to a decrease in the band gap of composite materials. Additional diagnostic methods are Raman spectroscopy and X-ray photoelectron spectroscopy, which analyze changes in the position of characteristic peaks, as well as the Kelvin probe method in scanning probe microscopy.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):764-778
764-778
About the prospects of the industrial production of the carbon nanomaterials from coal
Abstract
In this paper, an analysis of the current state of the domestic coal industry was carried out based on up-to-date statistical data, key challenges and risks associated with both global trends and factors of external economic pressure were described. As a possible measure to support the profitability of coal mining and ensure the socio-economic sustainability of the regions involved in this sphere, it is proposed to consider the production of carbon nanomaterials from coal. The rapidly growing market of carbon nanomaterials could provide an additional incentive for the development of knowledge-intensive and high-tech enterprises based on the coal industry. Various groups of methods allowing obtaining carbon nanomaterials from coal were considered, including ultrasonic liquid-phase exfoliation, hydro- and solvothermal synthesis, direct chemical synthesis, assuming no need for energy-consuming processes, mechanochemical activation, arc-discharge and plasmochemical methods, chemical vapor deposition. As part of the consideration of each of the approaches, a detailed description is given of the techniques that make it possible to obtain a wide variety of carbon nanomaterials: carbon quantum dots, graphene, carbon nanotubes, fullerenes. In conclusion, based on the information provided by the review, the most economically feasible production strategies are identified both in the short and long term.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):779-794
779-794
Identification of alkali metal clusters by field desorption
Abstract
The formation of clusters of potassium and cesium atoms on the surface of tungsten and rhenium crystals has been studied. The study was carried out using field electron microscopy, field desorption microscopy, and time-of-flight mass analysis of ions desorbed by an electric field. To determine the masses, particles adsorbed on the sample surface were desorbed with a high-voltage pulse lasting several ns, and the ion flight time from the sample to the detector was measured. The experiments were carried out in an ultrahigh vacuum (p < 10-9 Torr). Alkali metal atoms were deposited on the surface of tungsten and rhenium field emitters from an external spray. As a result of the measurements, not only monatomic alkali metal ions were detected, but also cluster ions containing up to seven atoms. The number of ions of each mass depended on the electric field strength on the surface of the emitters. As the field strength increases, the number of monatomic ions increases slightly at first and then decreases. In the opposite way, the number of cluster ions depends on the field strength. As the field increases, the number of cluster ions initially decreases, then increases. When a certain value of the field strength is reached, the emission of both monatomic and cluster ions stops. The described patterns are probably related to the movement of the field desorption zone, and, accordingly, the cluster identification area along the surface of the tip-shaped sample. The number of desorbed cluster ions reflects the cluster distribution over the sample surface. At low field strengths, ions are desorbed only from the area near the tip apex. This area consists of a densely packed crystal plane and wide steps surrounding this plane. As the tension increases, the desorption zone expands and passes through the rounded area of the surface between the flat faces, and the number of cluster ions decreases. Then, desorption begins from the lateral faces and steps, and the number of ion clusters being desorbed increases. Thus, it can be assumed that clusters are predominantly formed and located on a surface with steps of densely packed planes.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):795-804
795-804
Synthesis and study of disperse characteristics of selenium nanoparticles stabilized by octadecyltrimethylammonium bromide
Abstract
Within the framework of this work, the optimization of synthesis and study of dispersive characteristics of selenium nanoparticles stabilized by octadecyltrimethylammonium bromide was carried out, and the study of the aggregate stability of the obtained nanoparticles from the active acidity of the pH of the medium was carried out. At the first stage, quantum-chemical modeling of the interaction process of selenium nanoparticles stabilized by octadecyltrimethylammonium bromide was carried out, which resulted in the establishment that the addition of octadecyltrimethylammonium bromide forms an energetically favorable and chemically stable interaction. The interaction of OTAB with selenium occurs through the quaternary amino group and is energetically favorable (ΔE > 2399 kcal/mol) and chemically stable (0,031 ≤ η ≤ 0,057 eV). The synthesis was carried out using a chemical reduction method in an aqueous environment. Solution of selenous acid and octadecyltrimethylammonium bromide was prepared at a constant temperature and stirred, and a separate solution of the reducing agent, selenous acid, was added to the precursor solution with a stabilizer. The synthesis was optimized using an experimental design matrix with varying concentrations of system parameters. The samples were studied using photon correlation spectroscopy and acoustic electron spectroscopy. As a result of the research, it was found that the optimal sample has an average hydrodynamic diameter of 36 nm and a ζ-potential value of 46 mV. Then, the coagulation stability of selenium nanoparticles stabilized by octadecyltrimethylammonium bromide was studied in relation to changes in the pH of the medium. To conduct the study, buffer solutions with pH values ranging from 1,81 to 11,98 were prepared. The obtained samples of selenium nanoparticles stabilized by octadecyltrimethylammonium bromide were mixed with buffer solutions in a 1:1 ratio. As a result of the studies of the obtained samples, it was found that the change in the active acidity of the pH of the medium does not have a significant effect on the values of the average hydrodynamic diameter and ζ-potential of the samples at any point in the selected pH range of the medium.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):805-814
805-814
Morphological features of the breakdown and restoration of fibrillar collagen obtained by acetate extraction from tendon sheaths
Abstract
In hydrolysates of tendon sheaths obtained by acetate extraction of paravertebral tendons of laboratory rats, the stages of disintegration and reparative regeneration of fibrillar collagen were established. It was shown that collagen material is destroyed by a mechanism of the spinodal disintegration. In this case, the main anatomical fractions (tendon, sesamoid islets) exhibit different sensitivity to the action of an acidic agent — sesamoid islets are the most resistant, which may be due to the presence of proteoglycans resistant to acetate stress in the extrafibrillar matrix. The mechanisms of fibrillar collagen assembly correspond to the principle of its hierarchical organization. At the mesodimensional level, the predominant mechanisms of the self-assembly are «side-to-side» and «tip-to-tip» fusion, and the final forms are uni- and bipolar microfibrils. At the nanoscale level, the structural mechanism of fibrillar collagen growth is the twisting of microfibril spirals predominantly to the left as they mature. At the nanoscale level, fibril development occurs via the mechanism of intercalary growth with the formation of branched supramolecular formations.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):815-821
815-821
Effect of vanadate ions on the chemical precipitation of hydroxyapatite
Abstract
Ionic forms of V+5 are promising modifying agents for hydroxyapatite, endowing the biomaterial with increased solubility and antibacterial activity. Formation of vanadate-substituted hydroxyapatites was studied under conditions of precipitation from VO3–, HPO42–-containing solution with pH 10 and maturation for 4 days. It was shown that V+5 in apatitic structure represents V2O74– and VO43– ions, for which the characteristic bands in the Raman spectra are located at 920-917 cm–1, 897-882, 873-862 and 390-367 cm–1, respectively. Incorporation of VO43–-ions in the apatitic structure occurred in the entire studied range of [V]/[P] ratios from 1/8 to 1/1 due to its isomorphism with apatitic PO43--ions. Under precipitation conditions at [V]/[P]≥1/4, the apatitic structure accommodates V2O74–-ions, which prevail in the reaction medium with pH 10. Presence of V2O74–-ions provides deviation of the apatitic Ca/(V+P) ratio from stoichiometric value of 1,67 to 1,50 and contributes to a lowering of the size of apatitic crystallites formed from 14 nm to 6 nm. Heating at 800°C of vanadate-substituted hydroxyapatites with Ca/(V+P)<1,67 is accompanied by the removal of V2O74–-ions from the apatitic structure with formation of hydroxyapatite and tricalcium phosphate vanadate.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):822-830
822-830
Composition, properties and features of gallstones from human body
Abstract
A study of composition, properties and characteristics of gallstones extracted from the human body has been conducted. An analysis of the chemical composition and properties of stones has been established using a set of physico-chemical methods, which may contribute to a deeper understanding of mechanisms of their formation, which are still unknown. X-ray phase analysis showed that the stones under study are mixed, with a predominance of cholesterol in their composition. Special attention is paid to the detection of calcium phosphate, which may be a key factor in understanding the pathogenesis of gallstone disease, as this compound has not previously been detected in gallstones from different collections. To confirm the group composition of the stones, infrared Fourier spectroscopy was used, which revealed the conditions of absorption of bilirubin, represented as sodium bilirubinate. In addition, the average hydrodynamic radius of the nanopowder particles from the stones in the studied collection was determined by photon correlation spectroscopy, which made it possible to evaluate their dimensional characteristics. The study also carried out selective dissolution nanopowder from stones in order to identify the most effective solvent, which is of practical importance for understanding the properties and methods of lysis. The results of the work open up new horizons for further research in the field of bioorganic nanochemistry.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):831-840
831-840
Influence of the parameters of microwave catalytic pyrolysis of cellulose on the carbon nanostructures synthesis
Abstract
Carbon nanomaterials are a key component of developing nanotechnologies due to their unique characteristics and diverse applications. The production of biomass-based carbon nanostructures is considered a promising research area. Lignocellulosic materials are abundant carbon-rich renewable resources and have a sufficiently high potential to be converted into valuable carbon nanomaterials by various methods and technologies. Microwave pyrolysis is characterized as a process of thermochemical biomass conversion with improved energy efficiency and rapid heating. In this study, the catalytic synthesis of carbon nanotubes accompanying microwave pyrolysis of cellulose-containing feedstock using catalysts that are metal-modified graphite was investigated. It has been established that for obtaining multi-walled carbon nanotubes, the optimal metal content in the catalyst is 23-32%. Experiments studying the effect of microwave processing time on carbon nanostructure synthesis have demonstrated that carbon nanotubes formation mainly occurs during the first 3 minutes of exposure to ultra-high-frequency electromagnetic radiation. The possibility to exert a directed influence on the structure and morphology of the forming carbon nanomaterials by changing the synthesis parameters was shown. The products of microwave pyrolysis of cellulose have been characterized by transmission electron microscopy and X-ray phase analysis.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):841-850
841-850
In-situ modification of nanostructured hydroxyapatite by CdS particles
Abstract
The article discusses the possibility of obtaining functional composite materials with pronounced photocatalytic properties. A hybrid composite material has been developed by in-situ modification of nanostructured hydroxyapatite obtained by precipitation from solution with cadmium sulfide particles. The initial components and synthesized samples were certified using modern physicochemical methods of analysis: X-ray phase analysis, energy-dispersive X-ray analysis, Raman spectroscopy, scanning electron microscopy, and the Brunauer-Emmett-Teller method. The functional characteristics of the developed composite materials based on hydroxyapatite and cadmium sulfide, in particular, photocatalytic activity under the action of ultraviolet or visible radiation, have been studied. The efficiency of using the developed composite material as a photocatalyst was estimated by the oxidation rate of n-dihydroxybenzene (hydroquinone). Based on the obtained experimental data, the values of the reaction rate constants of photocatalytic oxidation of hydroquinone and its half-life under various conditions were calculated. It was proven that the developed composite material based on nanosized cadmium sulfide and hydroxyapatite has pronounced catalytic properties and is a promising material for use as a photocatalyst. A patent application has been filed for the developed composite material.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):851-864
851-864
Structural and kinetic aspects of hydroxyapatite and brushite dissolution in lactic acid
Abstract
Modern dentistry and regenerative medicine face the challenge of controlled removal of pathological calcium phosphate deposits and development of biocompatible materials for tissue restoration. This study presents a comprehensive investigation of lactic acid interaction with brushite (CaHPO4ꞏ2H2O) and hydroxyapatite (Ca10(PO4)6(OH)2), which is crucial for developing dental calculus demineralization methods and creating resorbable implants. The research employed advanced analytical techniques including potentiometry with a Ca-selective electrode, X-ray phase analysis, thermogravimetric analysis, and infrared spectroscopy. Special emphasis was placed on thermodynamic modeling of dissolution processes by Gibbs free energy calculation (ΔG° = -61,8 kJ/mol). The key results demonstrated that the calcium phosphate dissolution efficiency is critically pH-dependent: at pH < 4, the protonated form of lactic acid dominates, enabling active interaction, while at pH > 8,2 the process virtually ceases. The thermal analysis revealed the formation of calcium pyrophosphate (Ca2P2O7) at 400-800°C, which is significant for bioceramic material development. These findings provide new opportunities for creating pH-controlled demineralization systems and designing biomaterials with programmable resorption rates. The study has important practical implications for dentistry (dental calculus removal) and regenerative medicine (bone implants).
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):865-874
865-874
Investigation of the physicochemical properties of composite materials based on hydroxyapatite doped with individual substances and their combinations
Abstract
The paper studies the effect of reinforcing additives of titanium and zirconium oxides, as in individually and with their combined effect, on the physico-chemical properties of dispersed-hardened composite materials based on nanoscale hydroxyapatite obtained by precipitation from solution, followed by a heat treatment over a wide temperature range from 25 to 1200°C. The composite materials under study have been obtained by means of mechanochemical synthesis with simultaneous mixing and grinding of materials. The synthesized samples were certified by X-ray phase analysis, differential thermal analysis, and dispersion analysis. The influence of the qualitative and quantitative composition of the composite material on the sintering processes, strength characteristics and morphology of studied samples is shown. It has been experimentally established that the introduction of reinforcing additives, both individually and in combination, makes it possible to thermally stabilize the material up to temperatures of ~1200°C, while maintaining a constant phase composition, preventing the decomposition of hydroxyapatite into tricalcium phosphate. It is shown that the presence of zirconium dioxide in the sample composition makes it possible to significantly increase the compressive strength of the material. However, it was found that the combined presence of titanium and zirconium oxides in the ceramic material leads to a decrease in the microhardness of the composite, which in the case of these additives makes the use of double composites as medical materials more promising.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):875-886
875-886
Investigation of the process of stabilization of cobalt (II, III) oxide nanoparticles with alkyldimethylbenzylammonium chloride
Abstract
In this work, samples of cobalt (II, III) oxide nanoparticles stabilized with alkyldimethylbenzylammonium chloride were obtained by chemical precipitation in an aqueous medium. This material has a wide range of applications in electronics, agriculture, and medicine due to its magnetic, antibacterial, and conductive properties. Investigations were carried out using X-ray phase analysis, scanning electron microscopy, and infrared spectroscopy as well as quantum chemical modeling of the interaction of alkyldimethylbenzylammonium chloride and cobalt (II, III) oxide nanoparticles. During the study of the phase composition, it was found that the resulting sample has a cubic crystal lattice with a spatial face-centered group. Based on analysis of the microstructure, it was found that the sample was formed from irregularly shaped agglomerates ranging in size from 8 to 47 microns, consisting of spherical nanoparticles with a diameter from 50 to 75 nm. As a result of computer quantum chemical modeling, it was found that the interaction of cobalt (II, III) oxide nanoparticles with alkyldimethylbenzylammonium chloride is energetically favorable and chemically stable and occurs through nitrogen cation, which is confirmed by the results of infrared spectroscopy. Analysis of the obtained spectra showed that the interaction of cobalt (II, III) oxide with alkyldimethylbenzylammonium chloride occurs in the range of 1522-1630 cm-1 through the ionized amino group NH2+.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):887-897
887-897
Selection of optimal conditions for ion-exchange synthesis of yttrium aluminum garnet nanopowders on a cation-exchange matrix
Abstract
This paper presents an ion-exchange method for synthesizing yttrium aluminum garnet powders using a synthesized cation-exchange material based on sulfonated polystyrene. This material was obtained by heterogeneous sulfonation of polystyrene using concentrated sulfuric acid. Optimum synthesis conditions were determined, namely: the amount of the required cation-exchange material, the holding time in a solution containing Y3+ and Al3+ cations, and heat treatment conditions. It was found that compliance with these conditions allows obtaining single-phase products with the maximum yield. When deviating from the optimal conditions, the final product is contaminated with residues of the organic matrix and the intermediate product Y4Al2O9. The phase composition of the obtained samples was determined by powder X-ray diffraction methods; it corresponds to the garnet structure with the Ia3d space symmetry group. The paper presents studies of the particle surface morphology and determines the particle sizes of the powder using scanning electron microscopy. The samples are flake-shaped nanoparticles, the particle size varies from 30 to 100 nm, partially aggregated into clusters of sizes from 1 to 10 μm.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):898-905
898-905
Investigation of the effect of boron substitution impurities in carbon nanotubes on the interaction of polymethyl methacrylate with borocarbon nanotubes
Abstract
An analysis of the influence of boron impurities on the adsorption activity of boron-modified carbon nanotubes with respect to methyl methacrylate have been done. Research on the adsorption of methyl methacrylate can contribute to understanding mechanisms of sorption and help in the development of new functional materials. To complete the picture, the effect of boron concentration (from ~16% to 50%) on the final properties of the composite has been studied in the framework of the study. To predict the possibility of creating a stable «polymer-nanotube» complex, a theoretical study was performed using the quantum chemical density functional theory. The results were compared with the previously obtained results of a study of pure carbon nanotubes with a structural unit of methyl methacrylate. It has been found that polymethyl methacrylate molecules were adsorbed on the surface of nanotubes with significantly higher energy (~45-50%) than on pure nanotubes. The results of calculations of the electronic structure and electrostatic potentials have shown that a significant redistribution of the electron density occurs during the interaction between borocarbon nanotube and the methyl methacrylate monomer. This is expressed in an increase in the positive charge on the boron atom and an increase in the negative charge on the carbonyl oxygen of the monomer, which indicates the emergence of a strong donor-acceptor and Coulomb attraction between them. As a result, the structure of a borocarbon nanotube complex with methyl methacrylate was modeled. Its stability is ensured by physical adsorption, accompanied by a significant Coulomb contribution. Thus, borocarbon nanotubes, being p-type semiconductors, can provide better control over the electrical conductivity of the composite and create new ways for use in flexible electronics and sensors. It is also possible to expect a significant increase in the tensile strength, modulus of elasticity and impact strength of the composite with the same degree of filling due to the effective load transfer from the polymer matrix to the reinforcing bunts.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):906-915
906-915
Crystal structure and dispersed composition of multicomponent oxide (NiCoCrFeAl)xOy nanoparticles obtained via joint exploding wires
Abstract
Nanoparticle samples of (NiCoCrFeAl)xOy with 18, 30, and 35 at.% Al were synthesized via the joint electrical explosion of wires in an Ar + 25 mol.% O2. It has been established that spherical nanoparticles with a predominantly spinel-type crystal structure are formed during the joint electrical explosion of wires containing the specified metals in concentrations ranging from 5 to 35 at.%. The lattice parameter of the spinel phase decreases from 8,251 to 8,182 Å as the aluminum content increases from 18 to 35 at.%. Energy-dispersive spectroscopy data confirm a homogeneous distribution of metals within the nanoparticles. It is shown that it is necessary to take into account not only the ratio of metals in the explosion products, but also the thermodynamic conditions for the formation of nanoparticles. These conditions are determined by the pressure and thermal conductivity of the buffer gas used to obtain (NiCoCrFeAl)xOy nanoparticles with a given crystalline structure using the method of joint electrical explosion of wires.
Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. 2025;(17):916-927
916-927