Investigation of the Scattering of Low Energy Electrons from the Surface of Single Crystal Aluminum

Elastic and inelastic low energy electron diffraction (ELEED, ILEED) observations have been made on a clean surface of A1(100). Measurements on the (10) and (11) elastic diffraction beams were made using normally incident electrons in the energy range 30 ??? E ??? 170 eV. Peaks in the energy loss distribution are seen near 5, 10, 15, 26 and 31 eV, the dominant peaks near 10 and 15 eV corresponding to surface and bulk plasmon excitations respectively. Two types of structure are observed in the inelastic angular profiles: one closely correlated with the structure in the elastic angular profile, and the second being substructure corresponding to different ILEED conditions. Energy intensity profiles (as a function of incident energy) for the (10) and (11) elastic and inelastic diffraction beams have been measured. These profiles also show primary and secondary structure. Within the substructure of the angular and energy intensity profiles are the first experimental observations of sideband diffraction. A comparison of the experimental results and the theoretical predictions of Duke and Laramore and of Duke and Bagchi is made.This work was supported in part by the Joint Services Electronics Program (U. S, Army, U. S, Navy and U. S. Air Force) under Contract DAAB-07-67-C-0199, in part by the American Chemical Society, Petroleum Research Fund under Contract PRF 3668-A3,5, and in part by the Air Force Office of Scientific Research, Office of Aerospace Research, USAF, under Grant AFOSR-71-2034.Ope