Molecular Dynamics Simulations of Sputtering and Radiation Damage in Ionic Materials

This book describes MD simulations of sputtering and radiation damage in ionic materials. The multipole method implemented within an MD code has been used to evaluate the long-range Coulombic forces. Computer visualisation and animation techniques have been used extensively to display simulation results and to obtain information such as cluster ejection. In the study of radiation damage, they have also been used to interpret the damage caused to the lattice. For singly charged impacts (kinetic sputtering) in NaCl, it is found that there is a large amount of channelling and relatively low sputtering yields while for multiply charged impacts (potential sputtering) with [Ar]q+ (q = 1,4 and 8), a significant enhancement in the yields at low impact energies is observed. The higher energy single impact sputtering yields are much lower when compared with experimental results. Multiple impact simulations give yields that are more consistent with the observed experimental calculations. The models lead to a new explanation for the Coulomb explosion, which can occur when the surfaces of ionic systems are exposed to impact by highly charged particles.