Electron spectroscopy study of Pu and Pu compounds

Core-level and valence-band spectra of Pu and the other early actinide compounds show remarkable systematics, which can be understood in the framework of final state screening. For 4f core-level spectra, approaching 5f localization results in a change of screening mechanism of the core-hole, from f- to d-screening. In the transition region, both screening types coexist, leading to two-peak spectra with d- and f-screened components. A similar mixed-final-state-configuration is observed in the valence band spectra. Here the transition from itinerant to localized 5f character is observed as transition from band-like f-spectra (like in U) to f-screened and finally d-screened final state multiplet peaks of localized f-states. Observed multiplets resemble atomic multiplets, 5fn−1 for the d-screened, 5fn for the f-screened. This interpretation can be extended to the neighbouring actinide elements (Am and Np) and gives a consistent interpretation of spectra of many actinide compounds.