Work

Resonant inelastic x-ray scattering at the actinide M 4 , 5 -edges

Year: 2025

Type: article

Abstract: Understanding the electronic structure of actinide materials is crucial for both fundamental research and nuclear applications. The partially filled 5 f shells exhibit complex behavior due to strong correlations and ligand hybridization, requiring advanced spectroscopic techniques. Here, we report on the development and application of high-resolution valence band resonant inelastic x-ray spectroscopy (VB-RIXS) experiments at the uranium M 4 , 5 edges (3551 and 3725 eV). We present data of UO 2 , a well-established model actinide compound. VB-RIXS is particularly well suited for probing the 5 f -shell electronic structure, as it probes, in contrast to core-to-core RIXS, excitations without leaving a high-energy core hole in the final state. In VB-RIXS, we achieve energy resolutions of 50 meV ( M 5 ) and 90 meV ( M 4 ) , enabling the resolution of multiplet excitations and crystal-field effects, as well as charge-transfer and fluorescencelike features with unprecedented clarity. As such, high-resolution VB-RIXS offers direct insights into both low-energy, near-ground-state properties and high-energy hybridization and covalency effects. Our results demonstrate the power of VB-RIXS as a versatile and powerful tool for probing the strongly correlated electronic structure of actinide materials, providing essential input for quantitative modeling and the validation of theoretical concepts.

Source: Physical Review Research

DOI: 10.1103/twsv-xh5j