Electron energy loss spectra showing the effects of surface roughness and electromagnetic retardation-theory and experiment

We have developed a theory of electron energy loss (EEL) spectra that inclu des the effects of sample surface roughness and the electromagnetic retarda tion. The energy loss probability is given by the sum of the term arising f rom a perfect flat surface and the contribution from surface roughness. The theoretical predictions are compared with experimental EEL spectra of an e vaporated Au film. We find that the effects of both roughness and the elect romagnetic retardation must be incorporated in the theory to understand the experimental spectra.