ABSTRACT
In Chapter 3, the fundamental aspects of x-ray photoemission spectroscopy (XPS) were discussed. Especially, the importance of many-body charge-transfer effects in XPS was shown. For 3d XPS of mixed valence Ce compounds and 2p XPS of transition metal (TM) compounds, the charge-transfer effect causes a characteristic splitting of the XPS spectra, which provides us with important information of the electronic state. In the analysis of these spectra, the single impurity Anderson model (SIAM) or a cluster model without the intra-atomic multiplet effect works as a model of the starting approximation, and then the multiplet effect gives some corrections.
