Accurate global potential energy surface by extrapolation to the complete basis set limit and dynamics studies for...

The atomic ions with hydrogen reactions play important role in biological chemistry, atmospheric and combustion chemistry. In this work, a full three-dimensional global many-body expansion potential energy surface (PES) for the ground state of H₂S^-(²A') is reported for the first time, since there is almost no investigations can accurately and completely describe the PES. It is obtained using many-body expansion theory and an extensive set of accurate ab initio energies extrapolated to the complete basis set limit, for improving the accuracy of the potential energy surface. The topographical features of the new three-dimensional global potential energy surface are examined in detail, and found to be in good agreement with theoretical and experimental results. To better test the reaction, such a surface was applied to quasi classical trajectory calculations for S^-(²P)+H₂(¹Σ_g⁺)→SH^-(¹Σ)+H(²S) reaction. The integral cross sections, differential cross sections and the rate coefficients have been computed. Results indicate that such a work can be recommended for corresponding atmospheric dynamics studies and as building blocks for constructing the many body expansion potential energy surface of larger S^-/H containing systems.