2025/07/14 by Johan Vegelius, Vegelius, Johan, David K. Shuh +3
Chemistry · Materials Science · #FOS: Physical sciences #Nuclear Materials and Properties #Nuclear materials and radiation effects #Radioactive element chemistry and processing #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2507.10723
openalex publication_date 2025/07/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The 5f states were probed in ThO2 and U(VI) and U(V) oxides using x-ray absorption spectroscopy at the actinide O4,5 edges. Measured data were analyzed by several approaches including atomic, crystal-field theory and the Anderson impurity model to take into account the hybridization of actinide valence states with oxygen 2p states. For Th(IV), the 5f states are mainly affected by the crystal-field interaction with the closest neighbors as can be seen from the corresponding spectrum of ThO2. In turn, for U(VI) and U(V) oxides, the U 5f-O 2p hybridization and high degree of covalency in the chemical bonding play a decisive role increasing the 5f occupancy and consequently governing the ground and excited state properties. That is additionally illustrated by results from the calculations of the U 5d x-ray photoemission spectra for U(V) in the lattice of La-doped UO2.