Analysis of the High-Resolution Fourier Spectrum of the ν6 Band of the cis-C2h2d2 Molecule

Abstract

The spectrum of the ν₆ band of the cis-ethylene-d₂ molecule (cis-C₂H₂D₂) is recorded with a Bruker IFS 125 HR Fourier spectrometer in the range 580–1210 cm^–1 with resolution of 0.0021 cm^–1. An analysis of the experimental spectrum allows more than 1500 transitions belonging to this band to be assigned that by more than 2.5 times greater than it has been known in the literature so far. The obtained experimental data are then used to determine the model parameters of the molecule (the effective Hamiltonian in the A-reduction and I′- representation). Strong resonance interaction with the band ν₄ forbidden in absorption by the symmetry of a molecule is taken into account. 10 parameters of the Hamiltonian obtained by solving inverse spectroscopic problem reproduce 427 initial experimental energies (more than 1500 transitions) with accuracy close to the experimental uncertainty.