Amidani Lucia, Retegan Marius, Volkova Anna, Popa Karin, Martin Philippe M, Kvashnina Kristina O
The Rossendorf Beamline at ESRF, The European Synchrotron, 38043 Grenoble Cedex 9, France.
Institute of Resource Ecology, Helmholtz Zentrum Dresden-Rossendorf (HZDR), P.O. Box 510119, 01314 Dresden, Germany.
Inorg Chem. 2021 Nov 1;60(21):16286-16293. doi: 10.1021/acs.inorgchem.1c02107. Epub 2021 Oct 22.
We report here a detailed experimental and theoretical investigation of hexavalent uranium in various local configurations with a high-energy-resolution fluorescence-detected X-ray absorption near-edge structure at the U M edge. We show the pronounced sensitivity of the technique to the arrangement of atoms around the absorber and provide a detailed theoretical interpretation revealing the nature of spectral features. Calculations based on density functional theory and on crystal field multiplet theory indicate that for all local configurations analyzed, the main peak corresponds to nonbonding 5f orbitals, and the highest energy peak corresponds to antibonding 5f orbitals. Our findings agree with the accepted interpretation of uranyl spectral features and embed the latter in a broader field of view, which interprets the spectra of a large variety of U-containing samples on a common theoretical ground.
我们在此报告了一项详细的实验和理论研究，该研究利用高能分辨率荧光探测X射线吸收近边结构在U M边对处于各种局部构型的六价铀进行了研究。我们展示了该技术对吸收体周围原子排列的显著敏感性，并提供了详细的理论解释，揭示了光谱特征的本质。基于密度泛函理论和晶体场多重态理论的计算表明，对于所有分析的局部构型，主峰对应于非键合5f轨道，而最高能量峰对应于反键合5f轨道。我们的研究结果与铀酰光谱特征的公认解释一致，并将后者纳入了更广阔的视野，即在共同的理论基础上解释各种含铀样品的光谱。
