Séminaire LCPQ

Salle de séminaire IRSAMC

Rigorous theoretical studies of the electronic structure are presented that describe several near edge X-ray absorption fine structure, NEXAFS, edges in heavy metal systems. The presentation will focus on two aspects of the NEXAFS. One concern is show the importance of the spin-orbit splitting for the branching ratios, or relative intensities, of different multiplet split NEXAFS features. This is done by relating the intensity to selections rules for Russell-Saunders multiplets and relating the energies to the intermediate coupling of spin-orbit split levels. Another concern is for the consequences of multiplet and the ligand field splitting for the NEXAFS of U oxides where the U oxidation states changes between the oxides. An important objective is to establish direct relationships between features of the NEXAFS spectra and the chemical interactions in the oxides.