Multichannel Generalization of Multiple Scattering Theory. Application to the Analysis of Inner Shell X-Ray Spectra of Mixed-Valent Compounds

摘要

We outline a many-body description of the photoemission and photoabsorption processes that incorporates the multichannel treatment of the atomic dynamical excitations into the framework of the multiple scattering theory. In this way the interplay between excitation dynamics and electronic and geometrical structure of the ground state is elucidated. At the same time this approach provides a theoretical model for the study of the evolution from the adiabetic to the sudden regime. We derive a new multiple scattering expansion that takes into account interchannel transitions as well. As an application we discuss the homogeneous and inhomogeneous mixed-valent compounds, where the theory provides a clue at resolution of the ''threshold puzzle'' and sheds light onto the relation between photoemission and photoabsorption spectroscopy. (Atomindex citation 19:056447)