Probing Chemical Bonding in Uranium Dioxide by Means of High-Resolution X-ray Absorption Spectroscopy

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• 作者：Sergei M. ButorinAnders Modin ; Johan R. Vegelius ; Kristina O. Kvashnina ; David K. Shuh
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：December 29, 2016
• 年：2016
• 卷：120
• 期：51
• 页码：29397-29404
• 全文大小：437K
• ISSN：1932-7455

文摘

A systematic X-ray absorption study at the U 3d, 4d, and 4f edges of UO₂ was performed, and the data were analyzed within framework of the Anderson impurity model. By applying the high-energy-resolution fluorescence-detection (HERFD) mode of X-ray absorption spectroscopy (XAS) at the U 3d_3/2 edge and conducting the XAS measurements at the shallower U 4f levels, fine details of the XAS spectra were resolved resulting from reduced core-hole lifetime broadening. This multiedge study enabled a far more effective analysis of the electronic structure at the U sites and characterization of the chemical bonding and degree of the 5f localization in UO₂. The results support the covalent character of UO₂ and do not agree with the suggestions of rather ionic bonding in this compound as expressed in some publications.