Resonant inelastic x-ray scattering at the actinide M4,5-edges

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 M4,5 edges (3551 and 3725 eV). We present data of UO2, 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 (M5) and 90 meV (M4), 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 actinidematerials, providing essential input for quantitative modeling and the validation of theoretical concepts.

SUNDERMANN Martin;  HAHN Henrik;  CHRISTOVAM Denise;  HAVERKORT Maurits;  CACIUFFO Roberto;  KEIMER Bernhard;  TJENG Liu Hao;  SEVERING Andrea;  GRETARSSON Hlynur; 

2025-11-07

AMERICAN PHYSICAL SOCIETY

JRC144306

2643-1564 (online),   

https://journals.aps.org/prresearch/abstract/10.1103/twsv-xh5j,    https://publications.jrc.ec.europa.eu/repository/handle/JRC144306,   

10.1103/twsv-xh5j (online),