Application of High-Energy-Resolution X-ray Absorption Spectroscopy at the U L(3)-Edge to Assess the U(V) Electronic Structure in FeUO(4)

[Image: see text] FeUO(4) was studied to clarify the electronic structure of U(V) in a metal monouranate compound. We obtained the peak splitting of spectra utilizing high-energy-resolution fluorescence detection–X-ray absorption near-edge structure (HERFD-XANES) spectroscopy at the U L(3)-edge, which is a novel technique in uranium(V) monouranate compounds. Theoretical calculations revealed that the peak splitting was caused by splitting of the 6d orbital of U(V) in FeUO(4), which would be used to detect minor U(V) species. Such distinctive electronic states are of major interest to researchers and engineers working in various fields, from fundamental physics to the nuclear industry and environmental sciences for actinide elements.