Modeling hot-electron generation induced by electron promotion in atomic collision cascades in metals

Abstract

We present a computer simulation model for the investigation of electron promotion processes in atomic collision cascades in metals. The model combines molecular dynamics and molecular orbital calculations to describe the formation of hot electrons in close atomic collisions. We apply this model to a set of collision cascades initiated by the impact of a 5-keV silver atom onto an Ag(111) surface. The calculations show that about 15% of the bombarding energy originally introduced into the solid is dissipated into the generation of hot electrons in close collisions. Furthermore, we find that the nascent excitation energy spectrum closely resembles a power law $f({E}_{\text{exc}})\ensuremath{\propto}{E}_{\text{exc}}^{\ensuremath{-}\ensuremath{\delta}}$ with exponents $\ensuremath{\delta}\ensuremath{\approx}2--3$.