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Accueil > Séminaires > 2014

The chemistry and physics responsible for NEXAFS in heavy metal systems

Paul Bagus, University of North Texas (Denton, USA)

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.