Structures, vibrational spectra, and relative energies of HXSiS (X = H, F, and Cl) isomers

The potential energy surface for the decomposition of HXSiS (X = H, E and Cl) on the singlet state has been explored by B3LYP and CCSD(T) calculations. Five different types of reaction are proposed: (A) 1,1-HX elimination, (B) 1,2-H shift, (C) 1,2-X shift, (D) H· and XSiS· radical formation, and (E) X· and HSiS· radical formation. These results show interesting trends for the HXSiS isomers. Our theoretical investigations suggest that the doubly bonded species HXSi = S should be the lowest energy structure among the isomers from both kinetic and thermodynamic viewpoints. We also report theoretical predictions of molecular parameters and vibrational infrared (IR) spectra of the monohalogen-substituted silanethione, which should be useful for future experimental obsevations.