Vol 58, No 1 (2017)

A new method of solving the many-body Schrödinger equation is proposed. It is based on the use of constant particle-particle interaction potential surfaces (IPSs) and the representation of the many-body wave function in a configuration interaction form with coefficients depending on the total interaction potential. For these coefficients the corresponding set of linear ordinary differential equations is obtained. A hierarchy of approximations is developed for IPSs. The solution of a simple exactly solvable model and He-like ions proves that this method is more accurate than the conventional configuration interaction method and demonstrates a better convergence with increasing basis set.

The formation of structures obtained during the hydration and non-exchangeable absorption of phenylalanine by a low-basic AN-221 ion exchanger in the НСl form is modeled in the work. Quantum chemical calculations are made using the Gaussian 03 program implementing the B3LYP hybrid density functional with the 6-31G++(d,p) basis set. The sequence of hydration and dissociation of functional groups of the ion exchanger is determined, the structure is optimized, and its formation energy during the non-exchangeable sorption of phenylalanine by the AN-221 (НСl) anion exchanger is estimated.

In this work, the interaction of C₂₀ and the N₂H₂ fragment is investigated at the M062X/6-311G(d,p) level of theory in both gas and solution phases. The interaction energies obtained by the standard method are corrected by the basis set superposition error (BSSE) during the geometry optimization for all molecules at the same levels of theory. The results obtained from these calculations reveal that the interaction between C₂₀ and N₂H₂ increases in the presence of more polar solvents. Values of the electrophilic charge transfer show the charge flow from C₂₀ to N₂H₂. The influence of the solvent on the hyperpolarizability indicates that β_tot values decrease on passing from vacuum to the solution phase.

Solid solutions of zinc sulfide with manganese and cobalt are synthesized. Based on the analysis of X-ray diffraction profiles the conclusion is drawn about the formation of a hexagonal wurtzite type structure in the synthesized quantum dot (QD) solutions. The average crystallite sizes are 8 nm and 22 nm for the samples with manganese and cobalt respectively. Results of IR and optical spectroscopy are consistent with the powder X-ray diffraction and X-ray fluorescence data. The question about particle aggregation in isopropanol and DMF solutions is considered. The QD structures based on ZnS particles doped with Mn and Co transition metal atoms are modeled. The possibility to apply X-ray absorption near edge structure (XANES) spectroscopy to verify the atomic structure parameters around the positions of doping transition metal atoms in QDs of the ZnS family is shown. Partial densities of ZnS:Mn and ZnS:Co electronic states are calculated.

The structural characteristics of micelles from our previous work (Part I) are used to calculate the electrostatic energy of ions in the electric double layer on the surface of spherical ionic micelles in solutions of sodium n-alkyl sulfate homologues with the following number of carbon atoms in the molecule: n_C = 8, 10, 12, and 14. This energy is found to depend on the thickness of the electric double layer and its average radius on the surface of a micelle, the aggregation number, the degree of binding of counterions, and the dielectric constant. The developed semi-empirical method is used to calculate interfacial tensions in spherical micelles for the said homologues in solutions at their critical micellar concentrations and T = 303 K. These values are split into the contributions from the hydrophobic and electrostatic components. The electrostatic component of the interfacial tension in spherical micelles is compared with the expression for the ion–ion repulsion energy to obtain the values of static permittivity (dielectric constant) in the surface layer of micelles.

The crystal structure of a natural sulfide Cu_3,44Ag_0,56Pb₂Bi₆S₁₃ (Сmcm, Z = 4, a = 3.973(1) Å, b = 13.370(2) Å, c = 42.182(7) Å, R = 0.059) is determined. The structure has seven cation positions: two of them (Cu and Ag) are in a tetrahedral environment of sulfur atoms; one (Pb), in a special position (mm2), has a coordination polyhedron in the form of a bicapped trigonal prism; and the other cation positions are surrounded by sulfur atoms forming distorted octahedra. The mirror symmetry plane perpendicular to the c translation causes microtwinning by cutting a layer of trigonal prisms framed by tetrahedron ribbons. These layers are divided by those composed by edge-linked octahedra with a diagonal ribbon of five octahedra (N = 5). The cation and anion positions are ordered by individual sublattices with pseudohexagonal subcells on the m planes perpendicular to the a translation, which concentrate the positions of all the atoms. Supposedly, this natural sulfide is the previously described (1885) yet unconfirmed alaskaite mineral from the lillianite–heyrovskyite homological series and may be isostructural to the ourayite mineral.

The structures of two isostructural phases of [M(Еn)₃](ReO₄)₂ (M = Ni, Zn; Еn is ethylenediamine) are studied. The crystal structures belong to the triclinic system, but demonstrate a pseudohexagonal packing motif. It is shown that the product of thermal decomposition of [Zn(Еn)₃](ReO₄)₂ (hydrogen atmosphere, 400 °C) is a homogeneous mixture of nanocrystalline zinc and rhenium powders with coherent scattering regions of ~30 nm.

A new dimeric compound [{UO₂(μ-OH)(terpy)}₂](ClO₄)₂·0.67CH₃CN, containing an uranyl cation and a tridentate 2,2′:6′,2″-terpyridine (terpy) ligand, is synthesized from an acetonitrile solution of uranyl perchlorate and terpy. The crystal structure of the compound is determined by single crystal X-ray diffraction. The crystal structure shows the formation of symmetric and asymmetric cationic hydroxo-bridged uranyl dimers. The uranium atoms adopt a distorted pentagonal bipyramidal configuration with a UO₄N₃ coordination environment formed by two uranyl O atoms, three N atoms from the terpy ligand, and two O atoms from the hydroxide anions.

The crystal structure of the bimolecular crystal of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and methoxy-NNO-azoxymethane (МАМ) (1:2) is studied. The CL-20 molecules adopt a ζ-conformation. The crystal structure is formed by layers of CL-20 and МАМ molecules, between which there are shortened NO^δ–⋯N^δ+O contacts of the neighboring CL-20 and МАМ molecules.

A complex of physicochemical methods (powder XRD analysis, transmission and scanning electron microscopy, electron spectroscopy of diffuse reflectance, low-temperature nitrogen adsorption) is used for the comparative study of structural and morphological properties of oxide supports Ce_1–xM_xO_y (M = Gd, La, Mg; x = 0-0.5; 1.5 ≤ y ≤ 2.0) for catalysts for the autothermal reforming of bioethanol to a hydrogen-bearing gas. It is shown that Ce_1–xM_xO_y samples synthesized by the method of ester polymer precursors are mesoporous materials being the homogenous substitutional solid solutions with the fluorite-type cubic structure. The structural and textural properties of the Ce_1–xM_xO_y materials are regulated by varying the type of the dopant cation (M = Gd, La, Mg), the molar ratio M/Ce (0, 0.1, 0.25, 1), and heat treatment conditions (temperature 300-800 °C; duration 4-24 h). The relationship between the synthesis parameters and the characteristics of the Ce_1–xM_xO_y materials is found.

The molecular dynamics method is used to study liquid aqueous solutions of helium and neon, liquid water films and solid films with an ice II structure in helium and neon atmospheres, and solid solutions of helium and neon in ice II. Gas atoms wander randomly in water and make occasional slow jumps. The structure of the hydrate shell of the gas atoms bears little resemblance to the structure of ice II and other ice modifications. The solubility of neon in a water film is only a little higher than that of helium. Helium and neon atoms that find themselves in the channels of a thin ice II film make the same jumps along the channels as those along the channels in the structure of ice II crystals. The motions of two neon atoms in the neighboring (along the z axis) planes are correlated, whereas there is no correlation between the motions of helium atoms.

The solvent effects on the NH stretching of 1-(4-pyridyl)piperazine (1-4pypp, C₉H₁₃N₃) are investigated by density functional theory (DFT). The B3LYP hybrid density functional is used with the 6-311+G(3df,p) basis set in the polarizable continuum model (PCM). Computations are performed with 18 different polar or non-polar solvents. The calculated frequencies of the solvent-induced NH stretching vibrations are correlated with some solvent parameters such as the Kirkwood–Bauer–Magat (KBM) equation, the solvent acceptor number (AN), Swain parameters, and the linear solvation energy relationships (LSER). The present work explores the effects of the medium on the ν(NH) vibrations. The findings of this research can be useful for piperazines.

Zinc halide complexes of thionicotinamide (TNA) having the general formula [Zn(TNA)₂X₂] (X = Cl^–, Br^–, I^–) are prepared and characterized by thermal analysis, IR and NMR spectroscopy. The crystal structure of one of them, dichloridobis(thionicotinamide-κN)zinc(II), [Zn(TNA)₂Cl₂] (1), is determined using X-ray crystallography. In 1, the zinc atom is coordinated by two thionicotinamide ligands through nitrogen atoms and two chloride ions in a distorted tetrahedral coordination environment. The molecular structure of the complex is stabilized through intermolecular hydrogen bonding.

A new complex [Cu₂(L)₄(DMF)₂] (1) with benzoic acid (HL) as a ligand is synthesized by the solid phase synthesis method. Crystal data for the complex are as follows: monoclinic, space group P2₁/n, a = 10.593(2) Å, b = 10.123(2) Å, c = 16.336(3) Å, β = 93.55(3)°, V = 1748.4(6) ų, D_c = 1.439 g/cm^–3, Z = 4, F(000) = 780, GOOF = 1.003, final discrepancy factors R₁ = 0.0624, wR₂ = 0.1559. In 1, the Cu(II) ion is coordinated by six oxygen atoms to give a distorted octahedral coordination geometry. The electrochemical, fluorescent, and magnetic properties of 1 are studied. The results show that the electron transfer of 1 is quasi reversible in the electrode reaction corresponding to Cu(II)/Cu(I), and 1 exhibits three relatively strong fluorescent emission peaks at 403, 425, and 454 nm. In addition, complex 1 displays antiferromagnetism in a temperature range of 300 ~ 10 K.

Two iridium acetylacetonate complexes bearing axial bromide-substituted pyridine (3-bromopyridine, 1 and 4-bromopyridine, 2) are synthesized and their crystal structures are determined by single crystal X-ray diffraction. In both complexes, a distorted octahedral geometry of the central Ir(III) atom is formed by four oxygen atoms of two acetylacetone ligands, a carbon atom of one acetylacetone ligand, and a nitrogen atom of bromide-substituted pyridine.

Isostructural fluorooxalate complex compounds of indium(III) M₂[InF₃(C₂O₄)H₂O] (M = K, Rb), being the first representatives of a new class of mixed-ligand fluoro-containing complex compounds of indium(III) are synthesized and structurally studied for the first time. The crystal structures of M₂[InF₃(C₂O₄)H₂O] (M = K, Rb) are formed of K⁺ cations (Rb⁺ respectively) and complex [InF₃(C₂O₄)H₂O]^2– anions. The indium atom in the complex anion is surrounded by four F atoms, two of which are bridging, the oxygen atom of the coordinated H₂O molecule, and two oxygen atoms of the bis-bidentate (tetradentate) oxalate group. The coordination polyhedron of the indium atom (CN 7) is a pentagonal bipyramid. Via alternating double bridging F atoms and tetradentate bridging C₂O₄ group, the In(III) atom polyhedra are arranged in polymers chains. Via hydrogen O–H⋯F bonds the chains are organized in layers. Between the layers, the K⁺ or Rb⁺ cations are located, which strengthen the crystal structure.