Characteristics of chemical bonding of pentavalent uranium in La-doped UO2. Issue 1 (23rd November 2016)

• Record Type: Journal Article
• Authors: Butorin, Sergei M.; Kvashnina, Kristina O.; Prieur, Damien; Rivenet, Murielle; Martin, Philippe M.
• Is Part Of: Chemical communications. Volume 53:Issue 1(2017)
• Page Start: 115
• Page End: 118
• Publication Date: 2016-11-23
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1039/c6cc07684j
• Languages: English
• ISSNs: 1359-7345

Abstract

Abstract : HERFD-XAS studies clearly reveal U(v ) formation in the cubic environment in UO2 as a result of La doping. Abstract : The effect of La doping on the electronic structure of U in UO2 was studied using an advanced technique, namely, X-ray absorption spectroscopy (XAS) in the high-energy-resolution fluorescence-detection (HERFD) mode, at the U 3d3/2 (M4 ) edge. Thanks to a significant reduction of the core–hole lifetime broadening and distinct chemical shifts of the HERFD-XAS lines, the U(v ) formation as a result of La doping was identified. The isolated contribution of U(v ) in the M4 HERFD-XAS spectrum reveals the so-called charge-transfer satellites due to the U 5f–O 2p hybridization. The analysis of the experimental data within the framework of the Anderson impurity model (AIM) indicates a significant change in the characteristics and degree of covalency for the chemical bonding in the U(v ) subsystem of UO2 as compared to undoped UO2, which is a Mott–Hubbard system. The results are also supported by AIM calculations of X-ray photoelectron and optical absorption data.