A MODEL STUDY OF NONADIABATIC EFFECTS IN H-2 FRAGMENTATION

A model calculation is presented using time dependent quantum mechanics which examines the fragmentation of hydrogen molecules that scatter from a copper surface, H-2 + surface --> 2H + surface. The model treats a translational and a vibrational degree of freedom on two coupled diabatic surfaces corresponding to molecular and atomic motion. Results are presented for the dependence of the fragmentation distributions on the initial translational energy and vibrational state of the molecule for a potential topology that has an activation barrier to dissociative adsorption which is located late in the reaction path. It is round that quantum interferences can occur giving rise to Stuckelberg oscillations in the fragmentation distributions.