LIII-edge spectroscopy on cerium-based intermediate-valent compounds

In this paper, the ${\mathit{L}}_{\mathrm{III}}$-edge spectroscopy in cerium-based compounds is discussed in the framework of a single-impurity model. A few years ago, Gunnarsson and Schönhammer developed a model to describe photoemission in such systems. This model neglects the interaction between the photoelectron and the remaining system and then is not appropriate for ${\mathit{L}}_{\mathrm{III}}$ absorption. More recently, Jo and Kotani proposed an approach to describe the ${\mathit{L}}_{\mathrm{III}}$ edge of cerium oxide that accounts for the Coulomb interaction between the photoelectron, the f electron, and the core hole. I present a modification of this model by introducing a hybridization term between the photoelectron and the conduction states. A better agreement with experiment is then obtained for intermetallic compounds. Moreover, the phenomenological approach of the ${\mathit{L}}_{\mathrm{III}}$ edges used by most experimentalists is discussed.