Charakteristische Energieverluste bei der Streuung mittelschneller Elektronen an Aluminium-Oberflächen
The energy distributions of electrons scattered by variously treated (111) surfaces of aluminium crystals and their dependence on scattering angle has been measured by an electrostatic analyser with a spherical condenser. Etched surfaces show in the diffraction maxima discrete energy losses with intensities similar to those of thin aluminium foils. Electrolytically polished surfaces (H3PO4+CrO3 bath) show no diffraction patterns of Al, and the energy distribution is that of aluminium oxide. After removal of the oxide film, the diffraction pattern of even surfaces appears. In the diffraction maxima the intensity of the energy loss of 6·7 eV is high; the intensity of the energy loss of 14·9 eV increases with increasing order of the diffraction maxima. The angular distributions of the intensities of the discrete energy losses near the diffraction spots are similar to those observed at thin foils and agree with theory.