H2 dissociation dynamics on an alloy surface – controlling the dynamics via orientation

We demonstrate how we could influence the H2 dissociation dynamics through the H–H bond orientation (with respect to the surface) dependence of the potential energy (hyper-) surface (PES), by considering the interaction of H2 with an alloy surface (e.g., an ordered Cu3Pt(1 1 1)). Our preliminary results show that by changing the dependence of the PES on the H–H orientation (e.g., such that preference for H–H orientation perpendicular to the surface over intermediate H–H orientations between perpendicular and parallel occurs), not only did we observe a general increase in dissociation probability of H2, we also observe an increase in the dissociation probability of cartwheel-like rotating H2, relative to helicopter-like rotating H2. Depending on the initial state of the impinging H2 (initial rotational state and incidence energy), we also observed that the dissociation probability of cartwheel-like rotating H2 becomes even greater than the dissociation probabilities for rotating H2 with orientations intermediate between cartwheeling and helicoptering H2. Based on these results, we suggest how further information regarding the orientation dependence of the PES could be obtained experimentally.