Competition between exchange and dissociation processes in He+H₂⁺ collisions

Abstract

The dynamics of (He, H₂⁺) collisions on an accurate ab initio potential-energy surface (PES) has been investigated using the three-dimensional (3D) quasiclassical trajectory (QCT) approach for ν=0-5 and j=0 of H₂⁺ over a wide range of relative translational energies (E_trans) of the reactants. In addition to the substantial agreement between theory and experiment for the exchange reaction as was reported earlier, we find that the computed collision-induced dissociation (CID) cross section (σ^D) values and their dependence on ν and E_trans also are in near-quantitative accord with the available experimental results. The dominance of CID over exchange at high energies and the increase in the branching ratio Γ=σ^D/σ^E with ν are also nearly quantitatively reproduced by our computations, thus lending credence to the accuracy of the PES and the reliability of the trajectory approach.