CORE LEVEL PHOTOEMISSION IN SOLIDS

Many body effects in core level photoemission are discussed for rare earth systems, especially for La and Ce compounds both in metallic and insulating forms. The 3d core photoemission spectrum of these materials is analyzed by using the impurity Anderson mode1 incorporated with a core hole potential to the 4f state. Important informations on the metallic mixed valency, as well as on the insulating covalency, are derived from the analysis. The relationship of spectra between the 3d core photoemission and the 2p core photoabsorption is discussed