Molecular structure and force field of silicon dichloride and silicon dibromide from joint analysis of vibrational spectroscopic and electron diffraction data

Abstract

A joint analysis of electron diffraction and vibrational spectroscopic data has been performed for silicon dichloride and silicon dibromide. Various theoretical expressions for the model potentials have been tested. Both molecules appear to be rigid systems with small nuclear displacements and negligible vibrational anharmonicity. The equilibrium geometry and the force constants for both molecules have been determined and reliable deformation frequencies were estimated, viz., 195 ± 13 cm −1 and 130 ± 8 cm −1 for SiCl 2 and SiBr 2, respectively.