Electronic excitation in atomic collision cascades

A model is presented which allows to incorporate low-energy electronic excitation into the molecular dynamics simulation of atomic collision cascades. The model treats the electronic energy loss experienced by all moving atoms as a source term in a diffusive description of the electronic excitation energy transport. In order to acknowledge (i) the large temperature gradients and (ii) the local lattice disorder induced by the projectile impact, the electronic heat diffusivity is allowed to vary as a function of space and time across the cascade volume.