Physical information in polarized x-ray absorption spectroscopy and x-ray photoemission spectroscopy (invited) (abstract)

Abstract

Core level and localized level x-ray absorption spectroscopy and x-ray photoemission spectroscopy contain information that can be extracted in a way independent of the theory used for the valence band. The sum rule method essentially integrates over core hole effects, which average to zero, leaving only one-particle effects. The results present interesting problems for both localized and band structure theory. In particular, more information on orbital moments has already become available, which needs a correct treatment of spin-orbit coupling. On the other hand, the multiplet structure is for a large part due to interactions in the final state and therefore gives only indirect information on the ground state. The interpretation is more complex and theory dependent.