Molecular dynamics simulations of argon cluster impacts on a nickel film surface

In this study we probe the surface phenomena that occur on nickel thin films after argon cluster impacts by performing several simulations using various energies. The simulations are carried out based on a molecular dynamics (MD) approach. The argon cluster consists of 353 atoms with energies ranging from 1 keV to 3.0 keV. The simulation results show that when the incident energy is 1 keV, the surface retains its smoothness after impact although a slight thermal effect appears near the surface beneath the impact area. Increasing the argon cluster energy to 2 keV causes the atoms in the film to shift slightly under impact and a small hillock appears on the film surface after impact. When the cluster energy increases to 3 keV, a hemispherical crater will appear on the film surface after impact. In addition, a shock wave is generated within the film due to the impact, which propagates toward to the substrate in a hemispherical shape. These shock wave related phenomena are difficult to probe experimentally on an atomic level however molecular dynamics simulations are a suitable tool for investigating the shock wave phenomena in thin film.