Dissociation and predissociation on coupled electronic potential energy surfaces: A three-dimensional wave packet dynamical study

Abstract

The dissociation process of a triatomic molecule with strongly coupled electronic states is investigated by wave packet dynamics. Rotational and vibronic motion are separated for vanishing total angular momentum (J=0) in a linear molecule with conically intersecting Σ and Π electronic potential energy surfaces. All three remaining nuclear degrees of freedom are treated exactly. The time evolution of a wave packet prepared initially by photoionization of the neutral molecule is studied for different values of the nonadiabatic couplings and for different values of other relevant parameters. The potential surfaces studied include those modeling important aspects of the HCN+ system. Time dependent populations of diabatic and adiabatic electronic states are presented. The results can be interpreted by adapting ideas developed for vibronic coupling in bound systems to the dissociative situation.