US EPA

3703044 

Journal Article 

On the ground state electronic structure of uranium dioxide 

Krack, M 

2015 

1 

Physica Scripta
ISSN: 0031-8949 

90 

9 

10.1088/0031-8949/90/9/094014 

WOS:000362492500015 

Fully unconstrained cell optimizations of uranium dioxide (UO2) bulk model systems using the Gaussian plane waves method are presented. Different effective U-eff values are employed for various initial uranium 5f orbital occupation patterns in the framework of a spin polarized DFT+U approach based on the generalized gradient approximation proposed by Perdew, Burke, and Ernzerhof. The detected low-lying states are presented and their properties are analyzed. A new lowest energy state has been detected with a mixed 5f orbital occupation pattern different from the proposed ones so far which shows also favorable properties. The presented results are relevant for future investigations using DFT+U or hybrid functional methods for the study of actinide systems like UO2, especially defective ones. 

uranium dioxide; metastable states; DFT plus U; CP2K