First principles investigation of the structural and bonding properties of hydrated actinide (IV) oxalates, An(C2O4)2·6H2O (An = U, Pu)
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 (vdW) 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. For both U(C2O4)2·6H2O and Pu(C2O4)2·6H2O, the relaxed FM-spin structures were found to be higher in energy than the corresponding relaxed AFM-spin structures. The density of states based on AFM-spin configuration do not reveal a significant energy gap near the Fermi level of either system; however, hybridization between the actinide (Pu or U) 5f and O (2p) states is evident. Bader charge analysis also reveals significant covalent contributions in the An-O bonds of the actinide-oxalate layer of both U(C2O4)2·6H2O and Pu(C2O4)2·6H2O systems.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1557147
- Report Number(s):
- PNNL-SA-133111
- Journal Information:
- Computational Materials Science, Vol. 153
- Country of Publication:
- United States
- Language:
- English
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