FULL MULTIPLE-SCATTERING CALCULATIONS ON SILICATES AND OXIDES AT THE AL K-EDGE

We present full multiple-scattering calculations at the aluminium K ed ge that we compare with experiments for four crystalline silicates and oxide minerals. In the different minerals aluminium atoms are either fourfold or sixfold coordinated to oxygen atoms in Al sites that are p oorly symmetric. The calculations are based on different choices of on e-electron potentials according to aluminium coordinations and crystal lographic structures of the compounds. Hence it is possible to determi ne how the near-edge spectral features are a sensitive probe of the ef fective potential seen by the photoelectron in the molecular environme nt. The purpose of this work is to determine on the one hand the relat ion between Al K-edge spectral features and the geometrical arrangemen ts around the aluminium sites, and on the other hand the electronic st ructure of the compounds.