Using the random-phase approximation, we calculate the long-wavelength damping of the surface plasmon due to the periodicity of the lattice. The damping is the result of "vertical" interband transitions which create electron-hole pairs and is shown to be independent of the electronic structure perpendicular to the surface. An explicit calculation is performed for aluminum and the result agrees satisfactorily with the experimental values.

• Received 2 December 1974

DOI:https://doi.org/10.1103/PhysRevB.12.1995