Scattering of large argon clusters from a Pt(111) surface with low collision velocities Original Research Article

We report on classical trajectory calculations for Arn (n = 100 – 4400) scattering from a Pt(111) surface with low collision velocities. We investigate the effects of surface temperature, cluster size, and incident angle on energy transfer and fragmentation behavior. A cluster is first heated at surface impact and then by continuous heating by the surface while moving laterally tens of nanometers on the surface. When the cluster temperature reaches 130–180 K, extensive fragmentation takes place and the thermal excitation of the cluster forces it to leave the surface, which inhibits further temperature increase. A large number of small particles are ejected during this process, and large fragments may survive the surface interaction. The conditions favoring high cluster survival probability are: large cluster size, low incident velocity normal to the surface and high surface temperature. Final angular distributions for monomers are considerably broader than for large fragments. Monomers also have higher final velocities than large fragments, and the final distributions depend on the degree of surface corrugation. The results are concluded to qualitatively reproduce the general trends for angular and velocity distributions found in experimental data for similar scattering systems.