Impact of keV-energy argon clusters on diamond and graphite

Impact of keV-energy size-selected Arn (n = 16, 27, 41) cluster ions on diamond and graphite is studied both experimentally and by molecular dynamics simulations. For the case of diamond, relatively high cluster kinetic energies (above certain threshold) are required to produce severe radiation damage and originate crater formation on the surface. This is related to very strong chemical bonds and both the melting (or sublimation) point and thermal conductivity of diamond being the highest among the solids. For the case of graphite, which is layered material with weak van der Waals bonds between the graphene planes, significant radiation damage is already introduced by impact of clusters with low kinetic energies (a few tens of eV/atom). However, collisions of the argon clusters cause very elastic response of the graphene planes that leads to efficient closure of the craters which could be formed at the initial stage of impact.