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The relativistic all-electron ab initio calculations on the multiplet electronic structure of U3+ ion. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2020.110781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Mohapatra M, Rajeswari B, Hon NS, Kadam RM. Uranium luminescence in La 2 Zr 2 O 7 : effect of concentration and annealing temperature. LUMINESCENCE 2016; 31:1519-1523. [PMID: 27073058 DOI: 10.1002/bio.3138] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 03/10/2016] [Accepted: 03/12/2016] [Indexed: 11/07/2022]
Abstract
The speciation of a particular element in any given matrix is a prerequisite to understanding its solubility and leaching properties. In this context, speciation of uranium in lanthanum zirconate pyrochlore (La2 Zr2 O7 = LZO), prepared by a low-temperature combustion route, was carried out using a simple photoluminescence lifetime technique. The LZO matrix is considered to be a potential ceramic host for fixing nuclear and actinide waste products generated during the nuclear fuel cycle. Special emphasis has been given to understanding the dynamics of the uranium species in the host as a function of annealing temperature and concentration. It was found that, in the LZO host, uranium is stabilized as the commonly encountered uranyl species (UO22+ ) up to a heat treatment of 500 °C at the surface. Above 500 °C, the uranyl ion is diffused into the matrix as the more symmetric octahedral uranate species (UO66- ). The uranate ions thus formed replace the six-coordinated 'Zr' atoms at regular lattice positions. Further, it was observed that concentration quenching takes place beyond 5 mol% of uranium doping. The mechanism of the quenching was found to be a multipolar interaction. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- M Mohapatra
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-, 400085, India
| | - B Rajeswari
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-, 400085, India
| | - N S Hon
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-, 400085, India
| | - R M Kadam
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-, 400085, India
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Gupta SK, Pathak N, Kadam R. Probing local coordination and oxidation state of uranium in ThO2: U nanostructured. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2015.08.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lam OP, Anthon C, Heinemann FW, O’Connor JM, Meyer K. Structural and Spectroscopic Characterization of a Charge-Separated Uranium Benzophenone Ketyl Radical Complex. J Am Chem Soc 2008; 130:6567-76. [DOI: 10.1021/ja801007q] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oanh P. Lam
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Christian Anthon
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Frank W. Heinemann
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Joseph M. O’Connor
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Karsten Meyer
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, and Department of Chemistry and Pharmacy, Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, D-91058 Erlangen, Germany
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Lam OP, Feng PL, Heinemann FW, O'Connor JM, Meyer K. Charge-Separation in Uranium Diazomethane Complexes Leading to C−H Activation and Chemical Transformation. J Am Chem Soc 2008; 130:2806-16. [DOI: 10.1021/ja0766472] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oanh P. Lam
- University of California, San Diego, Department of Chemistry, 9500 Gilman Drive, La Jolla, California 92093, and University of Erlangen-Nürnberg, Department of Chemistry and Pharmacy, Inorganic Chemistry, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Patrick L. Feng
- University of California, San Diego, Department of Chemistry, 9500 Gilman Drive, La Jolla, California 92093, and University of Erlangen-Nürnberg, Department of Chemistry and Pharmacy, Inorganic Chemistry, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Frank W. Heinemann
- University of California, San Diego, Department of Chemistry, 9500 Gilman Drive, La Jolla, California 92093, and University of Erlangen-Nürnberg, Department of Chemistry and Pharmacy, Inorganic Chemistry, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Joseph M. O'Connor
- University of California, San Diego, Department of Chemistry, 9500 Gilman Drive, La Jolla, California 92093, and University of Erlangen-Nürnberg, Department of Chemistry and Pharmacy, Inorganic Chemistry, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - Karsten Meyer
- University of California, San Diego, Department of Chemistry, 9500 Gilman Drive, La Jolla, California 92093, and University of Erlangen-Nürnberg, Department of Chemistry and Pharmacy, Inorganic Chemistry, Egerlandstr. 1, D-91058 Erlangen, Germany
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Ruipérez F, Barandiarán Z, Seijo L. Quantum chemical study of 4f→5d excitations of trivalent lanthanide ions doped in the cubic elpasolite Cs2NaYCl6. Ce3+ to Tb3+. J Chem Phys 2005; 123:244703. [PMID: 16396559 DOI: 10.1063/1.2137689] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Wave-function-based ab initio calculations on the lowest states of the 4f(n),4f(n-1)5d(t2g)1, and 4f(n-1)5d(e(g))1 configurations of (LnCl6)3- clusters (Ln=Ce to Tb) embedded in the cubic elpasolite Cs2NaYCl6 have been performed, in an attempt to contribute to a comprehensive understanding of the 4f-->5d excitations of lanthanide ions in crystals. Reliable data are provided on the changes of bond lengths and breathing mode vibrational frequencies upon 4f-->5d(t2g) and 4f-->5d(e(g)) excitations, as well as on minimum-to-minimum and vertical absorption and emission transitions, and on the Stokes shifts. The available experimental data are discussed and predictions are made. The stabilization of the 4f-->5d(baricenter) excitation of the doped ions with respect to the 4f-->5d excitations of the free ions, which is a key variable for the understanding of these excitations in solid hosts, is analyzed and found to be due, in two-thirds, to dynamic ligand correlation effects and, in one-third, to orbital relaxation, charge transfer, and covalency effects present in a mean-field approximation.
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Affiliation(s)
- Fernando Ruipérez
- Departamento de Química, C-XIV, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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