First principles investigation of the structural and bonding properties of hydrated actinide (IV) oxalates, An(C2O4)2·6H2O (An = U, Pu)

Kerry E. Garrett; Andrew M. Ritzmann; Frances N. Smith; Sean H. Kessler; Ram Devanathan; Neil J. Henson; David G. Abrecht

doi:10.1016/j.commatsci.2018.06.033

First principles investigation of the structural and bonding properties of hydrated actinide (IV) oxalates, An(C₂O₄)₂·6H₂O (An = U, Pu)

Kerry E. Garrett, Andrew M. Ritzmann, Frances N. Smith, Sean H. Kessler, Ram Devanathan, Neil J. Henson, David G. Abrecht

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

The structural and bonding properties of actinide (IV) oxalates, U(C₂O₄)₂·6H₂O and Pu(C₂O₄)₂·6H₂O, are investigated using the generalized gradient approximation (GGA) to spin-polarized density functional theory (DFT) with van der Waals corrections. The GGA optimized structures, ground state magnetic moments, site-projected density of states, and Bader charges are reported. We calculate the energy differences between ferromagnetic (FM) and antiferromagnetic (AFM) spin configurations on the Pu or U sites to determine the preferred magnetic structure of these materials. The relaxed AFM-spin structure of Pu(C₂O₄)₂·6H₂O was found to be considerably lower in energy than the corresponding relaxed FM-spin structure; whereas, there was negligible energy difference in the relaxed AFM and FM-spin structures of U(C₂O₄)₂·6H₂O. Weak hybridization between the actinide (Pu or U) 5f and O (2p) states in the site-projected density of states suggests that these systems are ionic. Furthermore, Bader charge analysis reveals charges on the actinide and oxalate oxygen sites in both U(C₂O₄)₂·6H₂O and Pu(C₂O₄)₂·6H₂O that are similar to literature data on other actinide species which are ionic, in particular the actinide dioxides. Calculating the density of states using a Hubbard correction parameter of U = 4.0 eV based on the GGA + U method shows band gaps of ∼1 eV for Pu(C₂O₄)₂·6H₂O and ∼3 eV for U(C₂O₄)₂·6H₂O. Both systems are predicted to be charge-transfer insulators.

Original language	English
Pages (from-to)	146-152
Number of pages	7
Journal	Computational Materials Science
Volume	153
DOIs	https://doi.org/10.1016/j.commatsci.2018.06.033
State	Published - Oct 2018
Externally published	Yes

Funding

We thank Sebastien Kerisit for useful discussion and suggestions regarding this work. This work was supported by the Nuclear Process Science Initiative (NPSI) at the Pacific Northwest National Laboratory (PNNL) . Computational resources were provided by PNNL Institutional Computing (PIC). This work was performed at Pacific Northwest National Laboratory which is operated by the Battelle Memorial Institute for the U. S. Department of Energy under Contract No. DE-AC06-76RLO-1830.

Funders	Funder number
Nuclear Process Science Initiative
U.S. Department of Energy	DE-AC06-76RLO-1830
Pacific Northwest National Laboratory

Keywords

Bonding
Density functional theory
Electronic structure
Plutonium oxalate
Uranium oxalate

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10.1016/j.commatsci.2018.06.033

Cite this

@article{df31e6543e114745a4c459c8b0f53bfc,

title = "First principles investigation of the structural and bonding properties of hydrated actinide (IV) oxalates, An(C2O4)2·6H2O (An = U, Pu)",

abstract = "The structural and bonding properties of actinide (IV) oxalates, U(C2O4)2·6H2O and Pu(C2O4)2·6H2O, are investigated using the generalized gradient approximation (GGA) to spin-polarized density functional theory (DFT) with van der Waals corrections. The GGA optimized structures, ground state magnetic moments, site-projected density of states, and Bader charges are reported. We calculate the energy differences between ferromagnetic (FM) and antiferromagnetic (AFM) spin configurations on the Pu or U sites to determine the preferred magnetic structure of these materials. The relaxed AFM-spin structure of Pu(C2O4)2·6H2O was found to be considerably lower in energy than the corresponding relaxed FM-spin structure; whereas, there was negligible energy difference in the relaxed AFM and FM-spin structures of U(C2O4)2·6H2O. Weak hybridization between the actinide (Pu or U) 5f and O (2p) states in the site-projected density of states suggests that these systems are ionic. Furthermore, Bader charge analysis reveals charges on the actinide and oxalate oxygen sites in both U(C2O4)2·6H2O and Pu(C2O4)2·6H2O that are similar to literature data on other actinide species which are ionic, in particular the actinide dioxides. Calculating the density of states using a Hubbard correction parameter of U = 4.0 eV based on the GGA + U method shows band gaps of ∼1 eV for Pu(C2O4)2·6H2O and ∼3 eV for U(C2O4)2·6H2O. Both systems are predicted to be charge-transfer insulators.",

keywords = "Bonding, Density functional theory, Electronic structure, Plutonium oxalate, Uranium oxalate",

author = "Garrett, {Kerry E.} and Ritzmann, {Andrew M.} and Smith, {Frances N.} and Kessler, {Sean H.} and Ram Devanathan and Henson, {Neil J.} and Abrecht, {David G.}",

note = "Publisher Copyright: {\textcopyright} 2018",

year = "2018",

month = oct,

doi = "10.1016/j.commatsci.2018.06.033",

language = "English",

volume = "153",

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T1 - First principles investigation of the structural and bonding properties of hydrated actinide (IV) oxalates, An(C2O4)2·6H2O (An = U, Pu)

AU - Garrett, Kerry E.

AU - Ritzmann, Andrew M.

AU - Smith, Frances N.

AU - Kessler, Sean H.

AU - Devanathan, Ram

AU - Henson, Neil J.

AU - Abrecht, David G.

PY - 2018/10

Y1 - 2018/10

N2 - The structural and bonding properties of actinide (IV) oxalates, U(C2O4)2·6H2O and Pu(C2O4)2·6H2O, are investigated using the generalized gradient approximation (GGA) to spin-polarized density functional theory (DFT) with van der Waals corrections. The GGA optimized structures, ground state magnetic moments, site-projected density of states, and Bader charges are reported. We calculate the energy differences between ferromagnetic (FM) and antiferromagnetic (AFM) spin configurations on the Pu or U sites to determine the preferred magnetic structure of these materials. The relaxed AFM-spin structure of Pu(C2O4)2·6H2O was found to be considerably lower in energy than the corresponding relaxed FM-spin structure; whereas, there was negligible energy difference in the relaxed AFM and FM-spin structures of U(C2O4)2·6H2O. Weak hybridization between the actinide (Pu or U) 5f and O (2p) states in the site-projected density of states suggests that these systems are ionic. Furthermore, Bader charge analysis reveals charges on the actinide and oxalate oxygen sites in both U(C2O4)2·6H2O and Pu(C2O4)2·6H2O that are similar to literature data on other actinide species which are ionic, in particular the actinide dioxides. Calculating the density of states using a Hubbard correction parameter of U = 4.0 eV based on the GGA + U method shows band gaps of ∼1 eV for Pu(C2O4)2·6H2O and ∼3 eV for U(C2O4)2·6H2O. Both systems are predicted to be charge-transfer insulators.

AB - The structural and bonding properties of actinide (IV) oxalates, U(C2O4)2·6H2O and Pu(C2O4)2·6H2O, are investigated using the generalized gradient approximation (GGA) to spin-polarized density functional theory (DFT) with van der Waals corrections. The GGA optimized structures, ground state magnetic moments, site-projected density of states, and Bader charges are reported. We calculate the energy differences between ferromagnetic (FM) and antiferromagnetic (AFM) spin configurations on the Pu or U sites to determine the preferred magnetic structure of these materials. The relaxed AFM-spin structure of Pu(C2O4)2·6H2O was found to be considerably lower in energy than the corresponding relaxed FM-spin structure; whereas, there was negligible energy difference in the relaxed AFM and FM-spin structures of U(C2O4)2·6H2O. Weak hybridization between the actinide (Pu or U) 5f and O (2p) states in the site-projected density of states suggests that these systems are ionic. Furthermore, Bader charge analysis reveals charges on the actinide and oxalate oxygen sites in both U(C2O4)2·6H2O and Pu(C2O4)2·6H2O that are similar to literature data on other actinide species which are ionic, in particular the actinide dioxides. Calculating the density of states using a Hubbard correction parameter of U = 4.0 eV based on the GGA + U method shows band gaps of ∼1 eV for Pu(C2O4)2·6H2O and ∼3 eV for U(C2O4)2·6H2O. Both systems are predicted to be charge-transfer insulators.

KW - Bonding

KW - Density functional theory

KW - Electronic structure

KW - Plutonium oxalate

KW - Uranium oxalate

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U2 - 10.1016/j.commatsci.2018.06.033

DO - 10.1016/j.commatsci.2018.06.033

M3 - Article

AN - SCOPUS:85049085182

SN - 0927-0256

VL - 153

SP - 146

EP - 152

JO - Computational Materials Science

JF - Computational Materials Science

ER -

First principles investigation of the structural and bonding properties of hydrated actinide (IV) oxalates, An(C₂O₄)₂·6H₂O (An = U, Pu)

Abstract

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Keywords

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First principles investigation of the structural and bonding properties of hydrated actinide (IV) oxalates, An(C2O4)2·6H2O (An = U, Pu)

Abstract

Funding

Keywords

Access to Document

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Cite this

First principles investigation of the structural and bonding properties of hydrated actinide (IV) oxalates, An(C₂O₄)₂·6H₂O (An = U, Pu)