Effect of spin-orbit and on-site Coulomb interactions on the electronic structure and lattice dynamics of uranium monocarbide

Wdowik, U. D.; Piekarz, Przemysław; Legut, Dominik; Jagło, Grzegorz

doi:10.1103/physrevb.94.054303

Cited by 21 publications

(8 citation statements)

References 59 publications

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“…The description of the role of 5f electrons on different actinide–ligand interactions is important to understanding their chemistry, and computational approaches can provide useful information. Although computational studies of uranium monocarbide UC have been reported, − the properties of its excited states and ions have not been explored extensively. Wang et al , collected laser-evaporated carbon-rich U/C alloys in solid argon and neon matrices at 8 K to form UC, UCH, CUC, and U(CC) 2 .…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC^+/0/–

et al. 2022

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A combination of high-level ab initio calculations and anion photoelectron detachment (PD) measurements is reported for the UC, UC–, and UC+ molecules. To better compare the theoretical values with the experimental photoelectron spectrum (PES), a value of 1.493 eV for the adiabatic electron affinity (AEA) of UC was calculated at the Feller–Peterson–Dixon (FPD) level. The lowest vertical detachment energy (VDE) is predicted to be 1.500 eV compared to the experimental value of 1.487 ± 0.035 eV. A shoulder to lower energy in the experimental PD spectrum with the 355 nm laser can be assigned to a combination of low-lying excited states of UC– and excited vibrational states. The VDEs calculated for the low-lying excited electronic states of UC at the SO-CASPT2 level are consistent with the observed additional electron binding energies at 1.990, 2.112, 2.316, and 3.760 eV. Potential energy curves for the Ω states and the associated spectroscopic properties are also reported. Compared to UN and UN+, the bond dissociation energy (BDE) of UC (411.3 kJ/mol) is predicted to be considerably lower. The natural bond orbitals (NBO) calculations show that the UC0/+/– molecules have a bond order of 2.5 with their ground-state configuration arising from changes in the oxidation state of the U atom in terms of the 7s orbital occupation: UC (5f27s1), UC– (5f27s2), and UC+ (5f27s0). The behavior of the UN and UC sequence of molecules and anions differs from the corresponding sequences for UO and UF.

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Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC^+/0/–

et al. 2022

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“…65 Calculations for UC converged to paramagnetic solutions at low values of U and to ferromagnetic solutions at high values of U. While an antiferromagnetic state has recently been proposed for UC, 66 the precise ordering has not been established and we use the ferromagnetic ordering for consistency with previous computational studies. 17 The Heats of formation were computed using reference freeatom formation enthalpies for the C, N, O, Cl, and U atoms 67 and DFT atomization enthalpies for the uranium compounds.…”

Section: Methodsmentioning

confidence: 56%

“…Calculations for UC converged to paramagnetic solutions at low values of U and to ferromagnetic solutions at high values of U . While an antiferromagnetic state has recently been proposed for UC, the precise ordering has not been established and we use the ferromagnetic ordering for consistency with previous computational studies …”

Section: Methodsmentioning

confidence: 89%

Interplay between London Dispersion, Hubbard U, and Metastable States for Uranium Compounds

2021

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High-throughput computational studies of lanthanide and actinide chemistry with density-functional theory are complicated by the need for Hubbard U corrections, which ensure localization of the f-electrons, but can lead to metastable states. This work presents a systematic investigation of the effects of both Hubbard U value and metastable states on the predicted structural and thermodynamic properties of four uranium compounds central to the field of nuclear fuels: UC, UN, UO2, and UCl3. We also assess the impact of the exchange-hole dipole moment (XDM) dispersion correction on the computed properties. Overall, the choice of Hubbard U value and inclusion of a dispersion correction cause larger variations in the computed geometric properties than result from metastable states. The weak dependence of structure optimization on metastable states should simplify future high-throughput calculations on actinides. Conversely, addition of the dispersion correction is found to offset the repulsion introduced by the Hubbard U term and provides greatly improved agreement with experiment for both cell volumes and heats of formation. The XDM dispersion correction is largely invariant to the chosen U value, making it a robust dispersion correction for actinide systems.

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“…While spin–orbit effects were not included in our computed reaction energetics, a previous experimental and computational study of the U–H bond dissociation energy have shown that spin–orbit corrections can lower the energies of [UH] + and U + by 0.779 eV (75.2 kJ/mol) and 0.852 eV (85.2 kJ/mol), respectively. Based on previous reports, − we expect that spin–orbit effects for the U 5f orbitals could enhance the coupling between the singlet, triplet, and quintet potential energy surfaces …”

Section: Resultsmentioning

confidence: 83%

Conversion of a UO₂²⁺ Precursor to UH⁺ and U⁺ Using Tandem Mass Spectrometry to Remove Both “yl” Oxo Ligands

Terhorst,

Corcovilos,

van Stipdonk

2023

J. Am. Soc. Mass Spectrom.

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Multiple-stage collision-induced dissociation (CID) of a uranyl propiolate cation, [UO 2 (O 2 C−C�CH)] + , can be used to prepare the U-methylidyne species [O�U�CH] + [J . Am. Soc. Mass Spectrom. 2019, 30, 796−805]. Here, we report that CID of [O�U�CH] + causes elimination of CO to create [UH] + , followed by a loss of H • to generate U + . A feasible, multiple-step pathway for the generation of [UH] + was identified using DFT calculations. These results provide the first demonstration that multiple-stage CID can be used to prepare both U + and UH + directly from a UO 2 2+ precursor for the subsequent investigation of ion−molecule reactivity.

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Effect of spin-orbit and on-site Coulomb interactions on the electronic structure and lattice dynamics of uranium monocarbide

Cited by 21 publications

References 59 publications

Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC^+/0/–

Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC^+/0/–

Interplay between London Dispersion, Hubbard U, and Metastable States for Uranium Compounds

Conversion of a UO₂²⁺ Precursor to UH⁺ and U⁺ Using Tandem Mass Spectrometry to Remove Both “yl” Oxo Ligands

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Effect of spin-orbit and on-site Coulomb interactions on the electronic structure and lattice dynamics of uranium monocarbide

Cited by 21 publications

References 59 publications

Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC+/0/–

Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC+/0/–

Interplay between London Dispersion, Hubbard U, and Metastable States for Uranium Compounds

Conversion of a UO22+ Precursor to UH+ and U+ Using Tandem Mass Spectrometry to Remove Both “yl” Oxo Ligands

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Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC^+/0/–

Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC^+/0/–

Conversion of a UO₂²⁺ Precursor to UH⁺ and U⁺ Using Tandem Mass Spectrometry to Remove Both “yl” Oxo Ligands