Plasmon Damping in Metals

Abstract

A report is given of a theoretical and experimental investigation into the degree of plasmon damping in metals as a function of momentum transfer. A previous theoretical result by DuBois is corrected and extended by taking into account polarization effects. Measurements are reported of the change in half-width $\Delta E_{\frac{1}{2}}$ of the dispersed ≈15-eV aluminum plasmon energy-loss peak, excited by 20-keV electrons, as a function of electron scattering angle $\theta$. The results can be expressed in the form $\Delta E_{\frac{1}{2}}=A+B{\theta }^2+C{\theta }^4$, and there is good agreement between the values of $B$ and $C$ obtained from the revised theory and those found experimentally.