Theoretical X-ray spectroscopic study of 5f-electron signatures in actinide materials

Actinide materials are not only important for power generation nowadays, but also exhibit interesting physical properties from the condensed matter physics perspective. The valence 5f electrons in early actinides are considered to be delocalized, while in the late actinides the 5f electrons show localized behavior. Studying the local moment and 5f-electron occupations will shed insight into the electronic behavior in these materials. X-ray absorption spectroscopy (XAS) and X-ray photoemission spectroscopy (XPS) have been powerful tools to reveal the valence electronic structure with the assistance from theoretical calculations. In this work, we build a single-impurity Anderson model for the materials, and use exact diagonalization method to calculate its eigenenergies and eigenstates. The X-ray spectra are obtained by employing Fermi’s golden rule. Comparing the theoretical spectra with the experimental results provides a way to determine the 5f electronic signatures of the actinide materials, helping us understand the 5f electronic correlation effects.