ABINITIO HARTREE-FOCK AND POST-HARTREE-FOCK STUDIES OF MOLECULAR-STRUCTURES AND VIBRATIONAL-SPECTRA OF THIOFORMALDEHYDE AND ITS FLUORO, CHLORO, AND BROMO DERIVATIVES

Molecular parameters (bond lengths and bond angles, dipole moments, rotational constants) and vibrational IR spectra (harmonic wavenumbers, absolute intensities) of thioformaldehyde (CH2S) and its nine halides (CXYS, where X, Y = H, F, Cl, Br) are predicted at the ab initio HF and second-order Moller-Plesset perturbation theory (MP2 (full)) levels with a triple-zeta valence basis set augmented by polarization functions on all atoms. The molecular parameters and vibrational spectra of the title species calculated at the MP2 level agree very well with available experimental data. Reported data furnish reliable information on elusive molecular parameters and vibrational IR spectra of asymmetric halides and might be applied to identification of these species.