Influence of the polar angle of incidence on electronic substrate excitations in keV self-bombardment of solid silver

Abstract

We present a computer simulation study on the influence of the polar angle of incidence on electronic substrate excitations in the self-sputtering of silver. For the bombardment of a silver target with 5-keV Ag atoms, we employ a standard molecular dynamics code to follow the microscopic particle dynamics within the atomic collision cascade following the primary particle impact. The transfer of kinetic energy of cascade atoms into the electronic subsystem of the metal is treated in terms of the Lindhard model of electronic stopping and an electron promotion model describing the generation of hot electrons in close binary collisions. The transport of excitation energy away from the spot of generation is treated in a diffusive manner. The calculations yield a time- and space-dependent excitation energy density E(r→,t) that can be converted into an electron temperature profile Te(r→,t). The results of our calculations show an angle-dependent duration of the initial electron temperature peak at the surface which coincides with the time the projectile needs to cross the first layer of the model crystal.