Unimolecular dissociation of CH3SH+ near threshold: A theoretical study

The unimolecular dissociation of methanethiol cation (CH3SH+, 1) has been investigated theoretically. Ab initio and Gaussian-2 theory calculations have been performed to obtain the potential energy surface (PES) for loss of H and H2 from 1. On the basis of the PES obtained, the relative abundances of the two channels near threshold have been calculated by Rice-Ramsperger-Kassel-Marcus modeling. The calculated result agrees with the previous experimental one, suggesting that the dissociation occurs statistically near threshold on the ground electronic state.