Comparison of XAS spectra at the Al K-edge in garnets to multiple-scattering calculations

High-resolution x-ray absorption near-edge structures at Al K-edge were collected on a series of garnets, pyrope (Mg3Al2Si3O12), almandine (Fe3Al2Si3O12), spessartine (Mn3Al2Si3O12), and grossular (Ca3Al2Si3O12), using a YB66 crystal monochromator. Full multiple scattering (MS) calculations by using cluster models and different exchange-correlation potentials were compared with experimental data. An overall good agreement was obtained in the energy range up to 60 eV above the threshold and a clear evidence on the effect of atoms located far away from the first-coordination shell around the photoabsorber was obtained. Moreover the pre-edge feature can be explained in terms of the empty ''d'' bands of next nearest neighbors.