Predicting Kinetic Electron Emission in Molecular Dynamics Simulations of Sputtering†

We present a molecular dynamics (MD) based computer simulation model for particle bombardment of metal surfaces. In addition to the description of the atomic collision cascade initiated by the particle impact, our model incorporates the electronic degree of freedom of the target and therefore is capable of simultaneously predicting secondary ion formation in sputtering as well as ion-bombardment-induced kinetic electron emission (KEE). Hence, our simulation concept may be regarded as an approach to close the gap between classical MD simulations usually excluding electronic effects and ab initio many-body quantum mechanics breaking down for system sizes needed to describe atomic collision cascades. In this study, we apply our model to the keV self-bombardment of a (111)-oriented silver surface in order to predict kinetic electron emission yields.