Chemical effects in collision cascades

Although computer simulations of ion irradiation effects have shed much lig ht on the atom-level mechanisms of damage production in elemental materials , not much is known as to what extent the damage production is affected by the chemical composition of compounds. Using molecular dynamics simulations with realistic many-body potentials we now examine the irradiation effects in two quite different materials, covalently bonded GaAs and the metal all oy Cu3Au. The results show that the damage production and atom relocation d istances can be significantly different for the elemental constituents of t he compounds, and that the relative difference is likely to be most importa nt in relatively low-energy (similar to1 keV) cascades. (C) 2001 Elsevier S cience B.V. All rights reserved.