Quantum-classical simulations of the electronic stopping force and charge on slow heavy channelling ions in metals.

摘要: By simulating the passage of heavy ions along open channels in a model crystalline metal using semi-classical Ehrenfest dynamics we directly investigate nature non-adiabatic electronic effects. Our time-dependent tight-binding approach incorporates both an explicit quantum mechanical system and representation set classical ions. The coupled evolution electrons allows us to explore phenomena that lie beyond approximations made molecular simulations theories stopping. We report velocity-dependent charge-localization phenomenon not predicted by previous theoretical treatments channelling. This charge localization can be attributed excitation into defect states highly localized on channelling ion. These modes only become active when frequency at which ion moves from interstitial point equivalent matches corresponding excitations Fermi level states. Examining stopping force exerted system, find broad agreement with slow (a proportional velocity) for low velocity (up about 0:5 nm fs 1 our calculations), reduction power attributable effect higher velocities. exploiting simplicity structure are able illuminate physics behind processes observe present intuitive picture real-space, chemical perspective. (Some figures may appear colour online journal)