Quasiclassical Trajectory Study of Mg(3s3pP1) + H2 Reaction on Fitted ab Initio Surfaces

Abstract

Quasi-classical trajectory calculations for the reaction of Mg(3s3p1P1) with H2 are performed on two potential energy surfaces (PES), the excited state 1A‘ (or 1B2 in the C2v symmetry) in the entrance channel and the ground state 1A‘ (or 1A1) in the exit channel. A many-body expansion procedure is adopted for the construction of the analytical fit functions from the ab initio results. The title reaction involves a nonadiabatic transition between the two potential surfaces. For simplicity, the transition probability is assumed to be unity when the trajectory goes through the region of surface crossing and changes to the lower surface. The calculated total collisional deactivation and reaction cross sections decrease with the increase of translational collision energy. The calculated rotational product distributions are characterized by a bimodal feature both for the MgH v = 0 and 1 states. The trend of bimodality is consistent with the observation reported in experimental studies. Our inspection of individ...