TI AND O-K EDGES FOR TITANIUM-OXIDES BY MULTIPLE-SCATTERING CALCULATIONS - COMPARISON TO XAS AND EELS SPECTRA

Theoretical simulations and interpretations of x-ray-absorption near-e dge data at the Ti and O K edges in titanium oxides. rutile, and anata se, have been performed in the framework of full multiple scattering t heory and a tight-binding Linear muffin-tin orbital band-structure met hod. Good agreement between experimental data and theoretical calculat ions is obtained, especially in the preedge region of the Ti K-edge sp ectrum which is interpreted in terms of mixing between the central Ti 4p and neighboring Ti 3d orbitals in octahedral coordination. It is co ncluded that the positions of these latter Ti atoms relative to the ph otoabsorber influence in a noticeable way the intensity, width, and po sition of the features in the preedge region, which mainly originate f rom dipole transitions. Previous work on the subject is reexamined in the light of the present findings.