A MODEL FOR SURFACE DAMAGE IN ION-IRRADIATED SOLIDS

A model for defect production near the surface of an ion-irradiated so lid is developed based on the concept of local melting. The model show s that, as heat diffuses radially outward from the track of an ion, a cylinder of melt is created, and owing to the large volume change on m elting, pressure is developed in the liquid. Unlike displacement casca des In the interior of the crystal, the pressure is relieved by the vi scous flow of liquid through the surface. The results of the model are compared to results from molecular dynamics simulations and to experi mental observations.