Diabatic Potential Energy Surfaces of the H2S+ System and the Dynamics Studies of the S+ + H2 (v0 = 2, j0 = 0) Reaction

Abstract

Global diabatic potential energy surfaces (PESs) of the H₂S⁺ system, corresponding to the 1⁴A″ and 2⁴A″ electronic states, were built by using the neural network method. In ab initio calculations, the aug-cc-pVTZ basis set and MRCI-F12 method were adopted. The topographic features of the new diabatic PESs were discussed and compared with the available theoretical and experimental results in detail. The spectroscopic parameters obtained from the diabatic PESs are in good agreement with previous theoretical and experimental results. Based on the newly constructed diabatic PESs, the nonadiabatic dynamics calculations of the S⁺ + H₂(v₀ = 2, j₀ = 0) → SH⁺ + H reaction were carried out using the time-dependent wave packet method. To further understand the nonadiabatic effect, the adiabatic dynamical calculations of the title reaction were also performed based on the adiabatic PES, which was obtained by diagonalizing the diabatic PESs. The deviation between nonadiabatic results and adiabatic values is very obvious. In general, the adiabatic results underestimate the dynamics result at low collision energies and overestimate the dynamics results within high collision energy ranges. Therefore, to obtain accurate dynamics results, the nonadiabatic effect should be included in the calculation.