Energy-loss function including damping and prediction of plasmon lifetime

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 5 eV in Al and 6 eV in Au are predicted to be 2.18 fs and 1.70 fs, respectively. These predicted values are in reasonable agreement with those estimated from other measurements at the corresponding energies: 2.16 ± 0.22 fs in Al, and 1.91 ± 0.32 fs in Au.