Rotational relaxation of SH+ by collisions with He

Abstract

The first two-dimensional potential energy surface for the interaction between He and SH+(3Σ−) has been calculated using CCSD(T)/aug-cc-pVXZ(X = T,Q,5) supplemented by a three-term extrapolation scheme. This surface is subsequently employed in close coupling calculations to investigate the collision dynamics of SH+ with He atoms. The collisional cross sections for fine structure energy levels are computed. The de-excitation rate coefficients for the lower fine structure levels of SH+ molecules due to collisions with He are determined over a temperature range of 10–500 K.