Electronic excitations and their effect on the interionic forces in simulations of radiation damage in metals

摘要: Using time-dependent tight-binding simulations of radiation damage cascades in a model metal we directly investigate the nature excitations system quantum mechanical electrons response to motion set classical ions. We furthermore effect these on attractive electronic forces between find that are well described by Fermi-Dirac distribution at some elevated temperature, even absence direct electron-electron interactions would be required order thermalize non-equilibrium distribution. explain this result terms spectrum characteristic frequencies ionic motion. Decomposing force into four well-defined components within basis instantaneous eigenstates, accumulated weakening interionic bonds is mostly (95%) accounted for thermal excitations. This justifies use simplifying assumption thermalized electron with an temperature dependence and development temperature-dependent potentials.