STEP-FACILITATED DISSOCIATION OF SMALL METAL-CLUSTERS - A MOLECULAR-DYNAMICS STUDY

The motion of small Pt clusters at a step edge on the Pt(111) surface was studied by molecular-dynamics simulations using the corrected effe ctive-medium theory. It was found that interlayer diffusion of the clu sters proceeds via dissociation and consecutive single-atom exchanges with the edge atoms, rather than hopping over the edge as a unit. The dissociation and the exchanges occur in a coherent way. We therefore p ropose that surface defects, like steps or large vacancy pits, may fac ilitate cluster dissociation via incorporation of the cluster atoms in to the edges.