Stereodynamical Control of Nonadiabatic Quenching Dynamics of OH(A2S+) by H2: Full-Dimensional Quantum Dynamics

Abstract

The breakdown of the Born-Oppenheimer approximation is omnipresent in chemistry, but our detailed understanding of the nonadiabatic dynamics is still incomplete. In the present work, nonadiabatic quenching of electronically excited OH(A2S+) molecules by H2 molecules is investigated by a full-dimensional quantum dynamical method using a high quality diabatic potential energy matrix. Good agreement with experiment is found for the OH(X2P) ro-vibrational and L-doublet distributions. Furthermore, the nonadiabatic dynamics is shown to be controlled by stereodynamics, namely the orientation of the two reactants. The uncovering of a major (in)elastic channel, neglected in all previous analyses, resolves a long-standing experiment-theory disagreement concerning the branching ratio of the two electronic quenching channels.