MOLECULAR-DYNAMICS SIMULATION OF CLUSTER-ION FRAGMENTATION

Recent experiments have shown that it is possible to ''bounce'' low energy (few eV/atom) molecular ions from surfaces and observe the inelasticity of the rebound and the fragmentation patterns. In order to understand these data and to improve our intuition of such phenomena, we have performed molecular dynamics simulations of the impacts of Au clusters with barriers. These calculations not only allow us to deal with laboratory experiments but also give insight into the collisions of interstellar grains that result from the propagation of supernova-driven shock fronts through molecular clouds. In this case we want to determine to what extent the grains are heated and fragmented as a function of the shock velocity. The relevance of these results to the application of cluster-ion bombardment in thin-film deposition will also be discussed.