TY  - JOUR
AU  - Sundermann, Martin
AU  - Hahn, Henrik
AU  - Christovam, Denise S.
AU  - Haverkort, Maurits W.
AU  - Caciuffo, Roberto
AU  - Keimer, Bernhard
AU  - Tjeng, Liu Hao
AU  - Severing, Andrea
AU  - Gretarsson, Hlynur
TI  - Resonant inelastic x-ray scattering at the actinide M<sub>4,5</sub> -edges
JO  - Physical review research
VL  - 7
IS  - 4
SN  - 2643-1564
CY  - College Park, MD
PB  - APS
M1  - PUBDB-2025-04556
SP  - 043081
PY  - 2025
AB  - Understanding the electronic structure of actinide materials is crucial for both fundamental research and nuclear applications. The partially filled 5⁢𝑓shells 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<sub>4,5</sub> edges (3551 and 3725 eV). We present data of UO<sub>2</sub>, 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<sub>5</sub>) and 90 meV (𝑀<sub>4</sub>), 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. 
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1103/twsv-xh5j
UR  - https://bib-pubdb1.desy.de/record/639470
ER  -