Molecular dynamics simulations of low-energy cluster deposition on metallic targets

A modified version of the multiple interaction code SPUT2 was used to simulate impacts of 63-atom Al and Au clusters on 7-layer Au targets. For 1, 5, and 10 eV/atom Al and Au clusters, 50 impacts each were calculated up to a cutoff time of 2 ps. For each case studied, we found that the final shape and penetration depth of the incoming cluster was almost independent of the initial cluster position relative to the target. The 1 and 5 eV/atom Al clusters were flattened to less than 40% of their initial thickness and exhibited registration with the substrate at 2 ps. The 10 eV/atom Al clusters formed a poorly registered monolayer on the Au surface. In these higher-energy collisions a significant number of Al atoms were reflected from the Au surface. The 1 eV/atom Au clusters were flattened to approximately 60% of their initial thickness and also exhibited clear registration with the substrate at 2 ps. Higher-energy Au clusters penetrated deeply into the targets, causing substantial damage and crater formation.