Orientational effects on the dynamics of H-2 dissociation at the atop-Cu, atop-Pt, and Cu-Pt bridge sites of an ordered CU3Pt(111)

To demonstrate how we could influence the H-2 dissociation dynamics through the H-H bond orientation (with respect to the surface) dependence of H-2 d issociation, we considered the dissociation of H-2 on in ordered Cu3Pt(1 1 1). Our preliminary results show that by changing the dependence of the H-2 dissociation on the H-H orientation, such that preference for H-H orientat ion perpendicular to the surface over intermediate H-H orientations between perpendicular and parallel occurs, not only did we observe a general incre ase in dissociation probability of H-2 with initial rotational state (j = 1 ), we also observe a corresponding increase in the dissociation probability of cartwheel-like rotating H-2, relative to helicopter-like rotating H-2. Based on these results, we suggest how further information regarding the or ientation dependence of the H-2 dissociation could be determined experiment ally. (C) 2001 Elsevier Science B.V. All rights reserved.