Dynamics of cluster scattering from surfaces

Abstract
We have carried out stochastic trajectory simulations of the scattering of argon clusters, Arn, n=5 to 26, from a Pt(111) surface. At incident energies of 0.1 and 0.5 eV per atom, the clusters fragment almost completely into individual atoms. Some atoms remain trapped on the surface, but the majority scatter. For the larger clusters, the angular distributions of the scattered atoms peak near the surface tangent, and are almost independent of the incident angle. The mean kinetic energy of atoms is largest for those scattered near the surface tangent, and decreases as the scattering angle approaches the surface normal. These trends are in qualitative accord with the results of experimental studies of cluster scattering from surfaces. A multiple binary collision mechanism involving atom–atom collisions within the cluster as well as atom–surface collisions is responsible for this behavior.