Hybrid functional/embedded cluster study of uranium and actinide (actinide = Np, Pu, Am or Cm) mixed dioxides bulk and {110} surfaces

Chen, Jia-Li; Kaltsoyannis, Nikolas

doi:10.1016/j.jnucmat.2021.153490

Cited by 3 publications

(1 citation statement)

References 54 publications

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“…This includes the change from the more covalent early actinides to the more ionic mid and later elements, and the extensive range of oxidation states exhibited by the early elements diminishes significantly after Pu . The actinide dioxides, which are the subject of this work, change from Mott–Hubbard insulators to charge transfer insulators at PuO 2 . − UO 2 and NpO 2 have antiferromagnetic (AFM) ground states − while a nonmagnetic (NM) ground state is found for PuO 2 . , As PuO 2 is a product of the recycling of spent UO 2 nuclear fuel, detailed understanding of PuO 2 is clearly essential not just at a fundamental level but also to inform its safe current and long-term storage.…”

Section: Introductionmentioning

confidence: 91%

DFT + U Study of Uranium Dioxide and Plutonium Dioxide with Occupation Matrix Control

Chen

Kaltsoyannis

2022

J. Phys. Chem. C

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DFT + U with occupation matrix control (OMC) is applied to study computationally bulk UO 2 and PuO 2 , the latter for the first time. Using the PBESol functional in conjunction with OMC locates AFM and NM ground states for UO 2 and PuO 2 , respectively, in agreement with experimental findings. By simulating the lattice parameter, magnetic moment, band gap, and densities of states, U = 4.0 eV is recommended for AFM UO 2 , yielding data close to experiments for all considered properties. U = 4.5 and 4.0 eV are recommended for NM and AFM PuO 2 , respectively, though much larger U values (c. 10 eV) are required to yield the most recently reported PuO 2 band gap. For both oxides, several excited states have similar properties to the ground state, reinforcing the need to employ OMC wherever possible.

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Section: Introductionmentioning

confidence: 91%

DFT + U Study of Uranium Dioxide and Plutonium Dioxide with Occupation Matrix Control

Chen

Kaltsoyannis

2022

J. Phys. Chem. C

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Incorporation and migration of xenon in uranium-plutonium mixed nitride; A density functional theory study

Lin

Kaltsoyannis

2023

Journal of Nuclear Materials

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Formation of Fully Stoichiometric, Oxidation-State Pure Neptunium and Plutonium Dioxides from Molecular Precursors

Peterson,

Kelly,

Arino

et al. 2024

Inorg. Chem.

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Amidate-based ligands (N-(tert-butyl)isobutyramide, ITA) bind κ 2 to form homoleptic, 8-coordinate complexes with tetravalent 237 Np (Np(ITA) 4 , 1-Np) and 242 Pu (Pu(ITA) 4 , 1-Pu). These compounds complete an isostructural series from Th, U−Pu and allow for the direct comparison between many of the early actinides with stable tetravalent oxidation states by nuclear magnetic resonance (NMR) spectroscopy and single crystal X-ray diffraction (SCXRD). The molecular precursors are subjected to controlled thermolysis under mild conditions with the exclusion of exogenous air and moisture, facilitating the removal of the volatile organic ligands and ligand byproducts. The preformed metal−oxygen bond in the precursor, as well as the metal oxidation state, are maintained through the decomposition, forming fully stoichiometric, oxidation-state pure NpO 2 and PuO 2 . Powder X-ray diffraction (PXRD), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDS) elemental mapping supported the evaluation of these high-purity materials. This chemistry is applicable to a wide range of metals, including actinides, with accessible tetravalent oxidation states, and provides a consistent route to analytical standards of importance to the field of nuclear nonproliferation, forensics, and fundamental studies.

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Hybrid functional/embedded cluster study of uranium and actinide (actinide = Np, Pu, Am or Cm) mixed dioxides bulk and {110} surfaces

Cited by 3 publications

References 54 publications

DFT + U Study of Uranium Dioxide and Plutonium Dioxide with Occupation Matrix Control

DFT + U Study of Uranium Dioxide and Plutonium Dioxide with Occupation Matrix Control

Incorporation and migration of xenon in uranium-plutonium mixed nitride; A density functional theory study

Formation of Fully Stoichiometric, Oxidation-State Pure Neptunium and Plutonium Dioxides from Molecular Precursors

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