Analysis of the High-Resolution Rovibrational Spectrum of the C2H2D2-cis Molecule in the Region 1620–1780 cm–1

Abstract

The spectrum of the cis-ethylene-d2 molecule (C₂H₂D₂-cis) has been recorded with a Bruker IFS 120 HR Fourier spectrometer in the wavelength region 1100–2000 cm^–1 with a resolution of 0.0025 cm^–1. The region 1620–1780 cm^–1, in which the weak 2ν₇ (А1) and ν₆ + ν₁₀ (В₁) bands with centers at (1685.28900 ± 0.00069) cm^–1 and (1698.06400 ± 0.00033) cm^–1 are located, is considered. These bands have not been analyzed previously and are studied in the present work for the first time. The spectroscopic parameters are fitted using energies of 164 upper levels corresponding to the examined states. As a result, 10 parameters of diagonal blocks of the effective Hamiltonian describing the rovibrational structures of the 2ν₇ and ν₆ + ν₁₀ bands and 5 resonance parameters of the c-type Coriolis interaction are obtained.