Role of the density of conduction states on the L2,3 absorption spectrum of aluminum

The fine structure just above the L2,3 edge of aluminum at 72.72 eV has been examined with high resolution using the radiation of the Frascati electron synchrotron. A sensitive system providing normalization between the incident and transmitted light has allowed detection of absorption peaks not previously recorded in other measurements. It has been found that the optical response of the Al at these energies is strongly influenced by the oxide grown on its surface, so that corrections for the absorption of the oxide are necessary to yield only spectral features intrinsic to the metal. The results indicate that most of the fine structure of the L absorption spectrum is directly related to structure in the density of conduction-band states above the Fermi level.