Potential energy surface and quantum dynamics calculation of SH2− (2A′) based on ab initio scaled external correlation correction.

An accurate interatomic potential energy surface for ground state of SH2− is reported at the multireference configuration interaction level of theory using aug–cc–pVQZ basis set. The calculated ab initio energy points are utilized, after semi-empirically correcting the dynamical correlation by the many-body expansion-scaled external correlation method. To verify the accuracy of the potential energy surface, molecular reaction dynamics, including the relationship between reaction probability and collision energy, thermal rate constant, and integral scattering cross section are calculated by using the quantum time-dependent wave packet method. The final results show that our potential energy surface is accurate and the molecular reaction dynamics results are satisfactory, and the accurate potential energy surface and its dynamics results can also lay a foundation for the future experimental research of SH−-containing molecules. This study provides a reasonable ionic chemical dissociation channel for the dynamics, A global many-body expansion (MEB) PES is reported by fitting high-precision ab initio energies calculated at the multireference configuration interaction level with Davidson correction (MRCI(Q)) and the aug-cc-pVQZ basis set (AVQZ). By comparing with the integral cross section with experimental result, which have agreement with the previous experimental and theoretical values. Our theoretical results can provide effective support for future dynamic experiments. [ABSTRACT FROM AUTHOR]