Reactive Scattering Dynamics on Conically Intersecting Potential Energy Surfaces: The H + H2 Exchange Reaction

Abstract

We investigate the dynamics of a bimolecular reaction on conically intersecting potential energy surfaces. The flux operator method of calculating the state-specific total reaction probability is extended to a coupled-surface problem, both in the diabatic and adiabatic electronic representations. The reaction probabilities are calculated from their expectation values with the aid of a time-dependent wave packet (WP) approach. The initial WP is prepared in an adiabatic electronic state, and it is propagated in a suitable diabatic electronic representation. The initial state-specific and energy-resolved reaction probability is given in analytical forms in both the adiabatic and diabatic picture. The diagonal correction (Born−Huang term) to the uncoupled adiabatic (Born−Oppenheimer) Hamiltonian is discussed. The above formalism is applied to the H + H2 exchange reaction on its conically intersecting double many-body expansion (DMBE) potential energy surfaces. We report the initial state-selected reaction pro...