First-principles local density approximation (LDA)+U and generalized gradient approximation (GGA)+U studies of plutonium oxides

The electronic structures and properties of PuO₂ and Pu₂O₃ have been studied according to the first principles by using the all-electron projector-augmented-wave (PAW) method. The local density approximation (LDA)+U and the generalized gradient approximation (GGA)+U formalisms have been used to account for the strong on-site Coulomb repulsion among the localized Pu 5f electrons. We discuss how the properties of PuO₂ and Pu₂O₃ are affected by choosing the values of U and exchange-correlation potential. Also, the oxidation reaction of Pu₂O₃, leading to the formation of PuO₂, and its dependence on U and exchange-correlation potential have been studied. Our results show that by choosing an appropriate U it is possible to consistently describe structural, electronic, and thermodynamic properties of PuO₂ and Pu₂O₃, which enable the modelling of the redox process involving Pu-based materials.