Ion-induced collisional relocation of multicomponent targets

We investigate the assumptions on which various model calculations of concentration buildup under ion irradiation of multicomponent solids are based. The influence of different ingredients in binary-collision-based computer simulations of the preferential relocation of heavy and light target species is assessed. In particular, we analyze the choice of the model for the interaction potential, the free-flight path, electronic stopping, species of collision partner, etc. We conclude that the process of concentration buildup is affected most, and even changes its qualitative features, by the choice made in the part of the collision model which determines the species of the target atom interacting with the moving particle. The limitations in the description of low-energy atomic motion within the framework of a binary-collision model are discussed