An ab initio-based global potential energy surface for the SH(3) system and full-dimensional state-to-state quantum dynamics study for the H(2) + HS → H(2) S + H reaction.

An accurate potential energy surface for the ground electronic state of SH system has been constructed with 41,882 high level ab initio energy points and the neural network fitting method. The time-dependent wave packet method has been used to calculate the first state-to-state differential cross sections for the title reaction up to 1.2 eV in full dimensions, based on the reactant-product decoupling scheme. It is found that the majority of H S are produced in the ground vibrational state, with a large fraction of available energy for the reaction ending up as product translational motion. The differential cross sections at the threshold energy are dominated by a very narrow peak in the backward direction. With the increase of collision energy, the width of the angular distribution increases considerably, which is a typical feature of a direct reaction via abstract mechanism, similar to the H + OH → H O + H reaction. © 2018 Wiley Periodicals, Inc.