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Silva CL, Amidani L, Retegan M, Weiss S, Bazarkina EF, Graubner T, Kraus F, Kvashnina KO. On the origin of low-valent uranium oxidation state. Nat Commun 2024; 15:6861. [PMID: 39127780 PMCID: PMC11316815 DOI: 10.1038/s41467-024-50924-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 07/24/2024] [Indexed: 08/12/2024] Open
Abstract
The significant interest in actinide bonding has recently focused on novel compounds with exotic oxidation states. However, the difficulty in obtaining relevant high-quality experimental data, particularly for low-valent actinide compounds, prevents a deeper understanding of 5f systems. Here we show X-ray absorption near-edge structure (XANES) measurements in the high-energy resolution fluorescence detection (HERFD) mode at the uranium M4 edge for the UIII and UIV halides, namely UX3 and UX4 (X = F, Cl, Br, I). The spectral shapes of these two series exhibit clear differences, which we explain using electronic structure calculations of the 3d-4f resonant inelastic X-ray scattering (RIXS) process. To understand the changes observed, we implemented crystal field models with ab initio derived parameters and investigated the effect of reducing different contributions to the electron-electron interactions involved in the RIXS process. Our analysis shows that the electron-electron interactions weaken as the ligand changes from I to F, indicative of a decrease in ionicity both along and between the UX3 and UX4 halide series.
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Affiliation(s)
- C L Silva
- The Rossendorf Beamline at ESRF-The European Synchrotron, CS40220, 38043, Grenoble Cedex, France
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, 01314, Dresden, Germany
| | - L Amidani
- The Rossendorf Beamline at ESRF-The European Synchrotron, CS40220, 38043, Grenoble Cedex, France.
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, 01314, Dresden, Germany.
| | - M Retegan
- European Synchrotron Radiation Facility (ESRF), CS40220, 38043, Grenoble Cedex, France
| | - S Weiss
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, 01314, Dresden, Germany
| | - E F Bazarkina
- The Rossendorf Beamline at ESRF-The European Synchrotron, CS40220, 38043, Grenoble Cedex, France
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, 01314, Dresden, Germany
| | - T Graubner
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany
| | - F Kraus
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany
| | - K O Kvashnina
- The Rossendorf Beamline at ESRF-The European Synchrotron, CS40220, 38043, Grenoble Cedex, France.
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, 01314, Dresden, Germany.
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2
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Bagus PS, Nelin CJ, Schacherl B, Vitova T. Actinyl Electronic Structure Probed by XAS: The Role of Many-Body Effects. Inorg Chem 2024; 63:13202-13213. [PMID: 38980170 DOI: 10.1021/acs.inorgchem.4c00270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
A detailed analysis of the wave functions for the M5 to 5f excitations in the linear actinyls, UO22+, NpO22+, and PuO22+, and the theoretical X-ray absorption spectra obtained with these wave functions in comparison with experimental M5-edge high-resolution X-ray absorption near-edge structure (HR-XANES) spectra is presented. The wave functions include full treatment of scalar and spin-orbit relativistic effects through the use of a Dirac-Coulomb Hamiltonian; many-body effects are included in determining the wave functions. The character of the excited states and of the active spaces to describe the wave functions for these states are investigated and analyzed. It is shown that the excited states cannot, in general, be described with a single configuration but have an essential multiconfiguration character. The characterization of the properties of the excited states and the X-ray absorption spectra was achieved through the use of novel methods.
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Affiliation(s)
- Paul S Bagus
- Department of Chemistry, University of North Texas, Denton, Texas 76203-5017, United States
| | | | - Bianca Schacherl
- Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal (INE), P.O. 3640, D-76021 Karlsruhe, Germany
| | - Tonya Vitova
- Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal (INE), P.O. 3640, D-76021 Karlsruhe, Germany
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3
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Ehrman J, Shumilov K, Jenkins AJ, Kasper JM, Vitova T, Batista ER, Yang P, Li X. Unveiling Hidden Shake-Up Features in the Uranyl M 4-Edge Spectrum. JACS AU 2024; 4:1134-1141. [PMID: 38559711 PMCID: PMC10976573 DOI: 10.1021/jacsau.3c00838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 04/04/2024]
Abstract
The M4,5-edge high energy resolution X-ray absorption near-edge structure (HR-XANES) spectra of actinyls offer valuable insights into the electronic structure and bonding properties of heavy-element complexes. To conduct a comprehensive spectral analysis, it is essential to employ computational methods that accurately account for relativistic effects and electron correlation. In this work, we utilize variational relativistic multireference configurational interaction methods to compute and analyze the X-ray M4-edge absorption spectrum of uranyl. By employing these advanced computational techniques, we achieve excellent agreement between the calculated spectral features and experimental observations. Moreover, the calculations unveil significant shake-up features, which arise from the intricate interplay between strongly correlated 3d core-electron and ligand excitations. This research provides important theoretical insights into the spectral characteristics of heavy-element complexes. Furthermore, it establishes the foundation for utilizing M4,5-edge spectroscopy as a means to investigate the chemical activities of such complexes. By leveraging this technique, we can gain a deeper understanding of the bonding behavior and reactivity of heavy-element compounds.
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Affiliation(s)
- Jordan
N. Ehrman
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Kirill Shumilov
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Andrew J. Jenkins
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Joseph M. Kasper
- Theoretical
Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Tonya Vitova
- Institute
for Nuclear Waste Disposal (INE), Karlsruhe
Institute of Technology, P.O. Box 3640, Karlsruhe D-76021, Germany
| | - Enrique R. Batista
- Theoretical
Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ping Yang
- Theoretical
Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Xiaosong Li
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
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4
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Bagus PS, Nelin CJ, Rosso KM, Schacherl B, Vitova T. Electronic Structure of Actinyls: Orbital Properties. Inorg Chem 2024; 63:1793-1802. [PMID: 38232379 DOI: 10.1021/acs.inorgchem.3c03158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
A detailed analysis is presented for the covalent character of the orbitals in the actinyls: UO22+, NpO22+, and PuO22+. Both the initial, or ground state, GS, configuration and the excited configurations where a 3d electron is excited into the open valence, nominally the 5f shell, are considered. The orbitals are determined as fully relativistic, four component Dirac-Coulomb Hartree-Fock solutions. Several measures, which go beyond the commonly used population analyses, are used to characterize the covalent character of an orbital in order to obtain reliable estimates of the covalency. Although there are differences in the covalent character of the orbitals for the initial and excited configurations of the different actinyls, there is a surprising similarity in the covalent character for all of the states considered. This is true both between the initial and excited configurations as well as between the different actinyls. The analysis emphasizes the 5f covalent character in the closed shell bonding orbitals and the open shell antibonding orbitals since the focus is on characterizing orbitals needed in a many-body treatment of the actinyl wave functions. However, estimates are also made of the participation of the actinide 6d in the covalent bonding.
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Affiliation(s)
- Paul S Bagus
- Department of Chemistry, University of North Texas, Denton, Texas 76203-5017, United States
| | | | - Kevin M Rosso
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Bianca Schacherl
- Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal (INE), P.O. 3640, Karlsruhe, D-76021 Germany
| | - Tonya Vitova
- Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal (INE), P.O. 3640, Karlsruhe, D-76021 Germany
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5
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Tobin JG, Yu SW. Pu 5f Occupation in Plutonium Dioxide. Inorg Chem 2023; 62:2592-2598. [PMID: 36731118 DOI: 10.1021/acs.inorgchem.2c03202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
An actinide N4,5 branching ratio analysis of PuO2 and UO2 has been performed, including measurements with a scanning transmission electron microscope at the Advanced Light Source. It is shown that the 5f occupation of the Pu in plutonium dioxide is n = 5. This is contrary to recent results from another technique.
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Affiliation(s)
- J G Tobin
- University of Wisconsin-Oshkosh, Oshkosh, Wisconsin 54901, United States
| | - S-W Yu
- Lawrence Livermore National Laboratory, Livermore, California 94550, United States
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6
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Bagus PS, Nelin CJ, Brundle CR, Crist BV, Lahiri N, Rosso KM. Origin of the complex main and satellite features in Fe 2p XPS of Fe 2O 3. Phys Chem Chem Phys 2022; 24:4562-4575. [PMID: 35129561 DOI: 10.1039/d1cp04886d] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although the origin and assignment of the complex XPS features of the cations in ionic compounds has been the subject of extensive theoretical work, agreement with experimental observations remains insufficient for unambiguous interpretation. This paper presents a rigorous ab initio treatment of the main and satellite features in the Fe 2p XPS of Fe2O3. This has been possible using a unique methodology for the selection of orbitals that are used to form the ionic wavefunctions. This orbital selection makes it possible to treat both the angular momentum coupling of the open shell core and valence electrons as well the shake excitations from the closed shell orbitals associated with the O ligands into the valence open shell orbitals associated with the Fe 3d shell. This allows the character of the ionic states in terms of the occupations of the open shell core and valence orbitals and of the contributions of 2p1/2 and 2p3/2 ionization to the XPS intensities to be determined. Our analysis gives strong evidence that many body effects are essential for a correct description of the ionic states and, in general the states cannot be described by a single configuration over the open shell orbitals. An important consequence is that the Fe 2p XPS intensity in most of the features arises from small contributions from the ionization to many, tens to hundreds, of often unresolved ionic states. While the usual understanding of the lower binding energy main and satellite features as being dominantly from 2p3/2 ionization is confirmed, this is not the case for the higher binding energy features where 2p1/2 and 2p3/2 ionization and shake excitations in the valence space mix strongly. Furthermore, we have been able to show that a very large fraction, 88%, of the total Fe 2p XPS intensity is contained in a relatively small binding energy range of ∼35 eV. This is relevant if one wants to extract the stoichiometry of Fe2O3 from Fe 2p/O 1s intensity ratios. Similar considerations about the importance of many-body effects are likely to be relevant for other ionic compounds as well.
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Affiliation(s)
- Paul S Bagus
- Department of Chemistry, University of North Texas, Denton, TX 76203-5017, USA.
| | | | - C R Brundle
- C. R. Brundle and Associates, Soquel, CA 95073, USA
| | | | - N Lahiri
- Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Kevin M Rosso
- Pacific Northwest National Laboratory, Richland, WA 99352, USA
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7
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Schacherl B, Joseph C, Lavrova P, Beck A, Reitz C, Prüssmann T, Fellhauer D, Lee JY, Dardenne K, Rothe J, Geckeis H, Vitova T. Paving the way for examination of coupled redox/solid-liquid interface reactions: 1 ppm Np adsorbed on clay studied by Np M5-edge HR-XANES spectroscopy. Anal Chim Acta 2022; 1202:339636. [DOI: 10.1016/j.aca.2022.339636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 02/06/2022] [Accepted: 02/17/2022] [Indexed: 11/01/2022]
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8
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Sergentu DC, Autschbach J. X-ray absorption spectra of f-element complexes: insight from relativistic multiconfigurational wavefunction theory. Dalton Trans 2022; 51:1754-1764. [PMID: 35022645 DOI: 10.1039/d1dt04075h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
X-ray absorption near edge structure (XANES) spectroscopy, coupled with ab initio calculations, has emerged as the state-of-the-art tool for elucidating the metal-ligand bonding in f-element complexes. This highlight presents recent efforts in calculating XANES spectra of lanthanide and actinide compounds with relativistic multiconfiguration wavefunction approaches that account for differences in donation bonding in the ground state (GS) versus a core-excited state (ES), multiplet effects, and spin-orbit-coupling. With the GS and ES wavefunctions available, including spin-orbit effects, an arsenal of chemical bonding tools that are popular among chemists can be applied to rationalize the observed intensities in terms of covalent bonding.
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Affiliation(s)
- Dumitru-Claudiu Sergentu
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA.
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA.
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9
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Polly R, Schacherl B, Rothe J, Vitova T. Relativistic Multiconfigurational Ab Initio Calculation of Uranyl 3d4f Resonant Inelastic X-ray Scattering. Inorg Chem 2021; 60:18764-18776. [PMID: 34818001 PMCID: PMC8693175 DOI: 10.1021/acs.inorgchem.1c02364] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Indexed: 11/27/2022]
Abstract
We applied relativistic multiconfigurational all-electron ab initio calculations including the spin-orbit interaction to calculate the 3d4f resonant inelastic X-ray scattering (RIXS) map (3d3/2 → 5f5/2 U M4 absorption edge and 4f5/2 → 3d3/2 U Mβ emission) of uranyl (UO22+). The calculated data are in excellent agreement with experimental results and allow a detailed understanding of the observed features and an unambiguous assignment of all involved intermediate and final states. The energies corresponding to the maxima of the resonant emission and the non-resonant (normal) emission were determined with high accuracy, and the corresponding X-ray absorption near edge structure spectra extracted at these two positions were simulated and agree well with the measured data. With the high quality of our theoretical data, we show that the cause of the splitting of the three main peaks in emission is due to the fine structure splitting of the 4f orbitals induced through the trans di-oxo bonds in uranyl and that we are able to obtain direct information about the energy differences between the 5f and 4f orbitals: Δ5f δ/ϕ - 4f δ/ϕ, Δ5f π* - 4f π, and Δ5f σ* - 4f σ from the 3d4f RIXS map. RIXS maps contain a wealth of information, and ab initio calculations facilitate an understanding of their complex structure in a clear and transparent way. With these calculations, we show that the multiconfigurational protocol, which is nowadays applied as a standard tool to study the X-ray spectra of transition metal complexes, can be extended to the calculation of RIXS maps of systems containing actinides.
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Affiliation(s)
- Robert Polly
- Karlsruher Institut für Technologie
(KIT), Institut für Nukleare Entsorgung
(INE), Campus Nord, Postfach
3640, 76021 Karlsruhe, Germany
| | - Bianca Schacherl
- Karlsruher Institut für Technologie
(KIT), Institut für Nukleare Entsorgung
(INE), Campus Nord, Postfach
3640, 76021 Karlsruhe, Germany
| | - Jörg Rothe
- Karlsruher Institut für Technologie
(KIT), Institut für Nukleare Entsorgung
(INE), Campus Nord, Postfach
3640, 76021 Karlsruhe, Germany
| | - Tonya Vitova
- Karlsruher Institut für Technologie
(KIT), Institut für Nukleare Entsorgung
(INE), Campus Nord, Postfach
3640, 76021 Karlsruhe, Germany
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10
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Yu X, Sergentu DC, Feng R, Autschbach J. Covalency of Trivalent Actinide Ions with Different Donor Ligands: Do Density Functional and Multiconfigurational Wavefunction Calculations Corroborate the Observed "Breaks"? Inorg Chem 2021; 60:17744-17757. [PMID: 34747167 DOI: 10.1021/acs.inorgchem.1c02374] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A comprehensive ab initio study of periodic actinide-ligand bonding trends for trivalent actinides is performed. Relativistic density functional theory (DFT) and complete active-space (CAS) self-consistent field wavefunction calculations are used to dissect the chemical bonding in the [AnCl6]3-, [An(CN)6]3-, [An(NCS)6]3-, [An(S2PMe2)3], [An(DPA)3]3-, and [An(HOPO)]- series of actinide (An = U-Es) complexes. Except for some differences for the early actinide complexes with DPA, bond orders and excess 5f-shell populations from donation bonding show qualitatively similar trends in 5f n active-space CAS vs DFT calculations. The influence of spin-orbit coupling on donation bonding is small for the tested systems. Along the actinide series, chemically soft vs chemically harder ligands exhibit clear differences in bonding trends. There are pronounced changes in the 5f populations when moving from Pu to Am or Cm, which correlate with previously noted "breaks" in chemical trends. Bonding involving 5f becomes very weak beyond Cm/Bk. We propose that Cm(III) is a borderline case among the trivalent actinides that can be meaningfully considered to be involved in ground-state 5f covalent bonding.
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Affiliation(s)
- Xiaojuan Yu
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Dumitru-Claudiu Sergentu
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Rulin Feng
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
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