Electronic structure of uranyl complexes probed by valence and X-ray spectroscopy
Résumé
This presentation will showcase the capabilities of relativistic quantum chemistry approaches in exploring the electronic structure of actinide-containing compounds. The focus will be on luminescence properties and core-level spectroscopic observables of the uranyl moiety (UO22+) within both linear and bent uranyl complexes. Given the challenges associated with nuclear waste management and the environmental impact of fission products, efficient extraction and characterization methods for actinide-containing compounds are of great societal importance.
The electronic structure of actinide compounds remains poorly understood compared to other elements in the periodic table. Valence- and core-level spectroscopic techniques offer valuable insights into this complex subject. The presentation will demonstrate how luminescence spectroscopy and X-ray spectroscopies serve as sensitive tools for probing the electronic structure and bonding nature between the uranyl moiety and its coordinated ligands.
Specifically, the talk will cover the application of relativistic Time-Dependent Density Functional Theory (TDDFT) with the CAM-B3LYP functional. This method has proven effective in providing accurate excitation/emission energies and vibronic progressions for linear uranyl complexes (UO2Cl42-, UO2F53-, UO2(CO3)24-, UO2(NO3)L2), enabling the assignment of experimental data [1]. Additionally, the impact of bending the uranyl moiety on spectroscopy and observed vibronic progressions will be discussed [2].
The presentation will also delve into TD-DFT simulations of the core spectra of the uranyl tetrachloride dianion (UO2Cl42-) in the Cs2UO2Cl4 crystal. These simulations align with previously reported angle-resolved near-edge X-ray absorption spectroscopy (NEXAFS) at the oxygen K-edge and high-energy resolution fluorescence detected (HERFD-XANES) at the uranium M4- and L3-edges [3].
[1] H. Oher et al. Inorg. Chem. 2020, 59 5896; H. Oher et al. Inorg. Chem. 2020, 59, 15036; H. Oher et al. Inorg. Chem. 2022, 61, 890.
[2] H. Oher et al. Inorg. Chem. 2023, 62, 9273–9284.
[3] W. A. Misael, A. S. P. Gomes, Inorg. Chem. 2023, 62, 11589–11601.
The electronic structure of actinide compounds remains poorly understood compared to other elements in the periodic table. Valence- and core-level spectroscopic techniques offer valuable insights into this complex subject. The presentation will demonstrate how luminescence spectroscopy and X-ray spectroscopies serve as sensitive tools for probing the electronic structure and bonding nature between the uranyl moiety and its coordinated ligands.
Specifically, the talk will cover the application of relativistic Time-Dependent Density Functional Theory (TDDFT) with the CAM-B3LYP functional. This method has proven effective in providing accurate excitation/emission energies and vibronic progressions for linear uranyl complexes (UO2Cl42-, UO2F53-, UO2(CO3)24-, UO2(NO3)L2), enabling the assignment of experimental data [1]. Additionally, the impact of bending the uranyl moiety on spectroscopy and observed vibronic progressions will be discussed [2].
The presentation will also delve into TD-DFT simulations of the core spectra of the uranyl tetrachloride dianion (UO2Cl42-) in the Cs2UO2Cl4 crystal. These simulations align with previously reported angle-resolved near-edge X-ray absorption spectroscopy (NEXAFS) at the oxygen K-edge and high-energy resolution fluorescence detected (HERFD-XANES) at the uranium M4- and L3-edges [3].
[1] H. Oher et al. Inorg. Chem. 2020, 59 5896; H. Oher et al. Inorg. Chem. 2020, 59, 15036; H. Oher et al. Inorg. Chem. 2022, 61, 890.
[2] H. Oher et al. Inorg. Chem. 2023, 62, 9273–9284.
[3] W. A. Misael, A. S. P. Gomes, Inorg. Chem. 2023, 62, 11589–11601.
