Energy-loss function including damping and prediction of plasmon lifetime

Abstract

An approach to include plasmon damping in the energy-loss function is described within the dielectric theory. Use of the energy-loss function included damping for calculating the electron inelastic mean free path yields results in good agreement with the experimental data and other theoretical results at medium–high energies. At a few eV above the Fermi energy, the present results are entirely consistent with those obtained from other measurements for Au. Also, a simple way to predict the values of damping and lifetime at low energies is described. Two values of lifetime for an electron with energy (above the Fermi energy) of 5eV in Al and 6eV in Au are predicted to be 2.18fs and 1.70fs, respectively. These predicted values are in reasonable agreement with those estimated from other measurements at the corresponding energies: 2.16 ± 0.22fs in Al, and 1.91 ± 0.32fs in Au.