Molecular dynamics computer simulations were used to study damage production mechanisms at solid surfaces during bombardment with keV ions. Three separate mechanisms were identified. These were ballistic damage, viscous flow and micro-explosions. Ballistic damage was created by the direct knock-on of atoms into the surface as described by the binary collision approximation. Viscous flow involved local melting and the forced flow of liquid onto the surface. Micro-explosions occurred when the high pressures in cascades led to rupture of the nearby surface. The relative importance of each mechanism depended upon the atomic mass, melting point, atomic density, structure and atomic bonding of the target, and upon the mass and energy of the projectile. The simulations were performed for self-atom bombardment. Cascades in the interior were also examined, for comparison with surface events. Several events of 4.5keV Ne and Xe bombardment of Pt(111) were simulated.

Molecular Dynamics Investigations of Surface Damage Produced by keV Self-Bombardment of Solids. M.Ghaly, K.Nordlund, R.S.Averback: Philosophical Magazine A, 1999, 79[4], 795-820