Incorporating non-adiabatic effects in Embedded Atom potentials for radiation damage cascade simulations

摘要

In radiation damage cascade displacement spikes ions and electrons can reachvery high temperatures and be out of thermal equilibrium. Correct modelling ofcascades with molecular dynamics should allow for the non-adiabatic exchange ofenergy between ions and electrons using a consistent model for the electronicstopping, electronic temperature rise, and thermal conduction by the electrons.We present a scheme for correcting embedded atom potentials for thesenon-adiabatic properties at the level of the second-moment approximation, andparameterize for the bcc transition metals above the Debye temperature. We usehere the Finnis-Sinclair and Derlet-Nguyen-Manh-Dudarev potentials as modelsfor the bonding, but the corrections derived from them can be applied to anysuitable empirical potential.