First-principles DFT +U calculations on the energetics of Ga in Pu, Pu2O3 and PuO2

Stability and optical properties of plutonium monoxide from first-principle calculation

“…Within the above computational schemes, the lowest-energy magnetic states of δ -Pu and PuO are AFM, while that of α -Pu 2 O 3 is FM for pure DFT and AFM for DFT +  U . These findings are in accord with the previous literature 24,31–36,40 .…”

“…These choices were already proved to give a reasonable description of Pu 24 and Pu 2 O 3 31,32 . In addition, scalar relativistic calculations were performed using spin-orbit coupling (SOC) but SOC was not included in the enthalpy calculation because it is already found that the inclusion of SOC has insignificant effect on the bulk properties 24,31–36 . For example, within GGA, inclusion of SOC increases the equilibrium lattice parameter of PuO by only 0.14%.…”

Oxygen Vacancy Formation and Water Adsorption on Reduced AnO2{111}, {110}, and {100} Surfaces (An = U, Pu): A Computational Study

“…Two groups have calculated the oxygen vacancy formation energy for both UO2 and PuO2. 35,38,44,45 Although the values differ substantially between the groups (one set of studies used GGA and the other GGA+U), both found that the formation energy is higher in UO2 than PuO2. and, perhaps surprisingly considering the higher surface energy and lower coordination of surface oxygen atoms on the {100} than {110} surface, the {100} surface had a value higher than the {110} surface (1.61 eV).…”

Plutonium Oxidation States in Complex Molecular Solids

“…All DFT + U calculations in Dudarev formalism are performed using the Vienna Ab initio Simulation Package, Perdew–Burke–Ernzerhof (PBE) exchange-correlation functional, and projector augmented wave (PAW) pseudopotential. − An effective U value of 4.0 eV is used for Pu 5f electrons; this value or thereabouts has been widely used and proven by ourselves and other researchers to be reasonable in describing the localization degree of Pu 5f electrons in a variety of solid-state compounds. ,,,,− In fact, our calculation tests show that U values in the range of 3–5 eV do not influence the assignments of OS qm despite that the occupation numbers slightly increase with the increase in U . Relaxations for the large molecular crystals are constrained to volume optimization and Monkhorst–Pack Γ-point sampling, and the convergence is reached when the total energies converge within 1 × 10 –5 eV and Hellmann–Feynman forces on each ion are lower than 0.02 eV/Å.…”

“…This holds for the some nonmetallic elements such as H and N with weak oxidizability judged from their borderline compounds PuH 3 and PuN . Pu 2+ had not been detected in the binary compounds for a long time; even the unstable PuH 2 and PuO (exactly, stabilized by C, i.e., PuC x O 1– x ) were determined to be trivalent-like Pu ions with a surplus 5f conduction electron, resulting in the metallic states of PuH 2 and PuO, whereas PuH 3 and Pu 2 O 3 are semiconducting states. − Clearly, the valence or OS can be readily changed by more electronegative elements. With the transition of Pu 2 O 3 → PuO 2 → PuO 2+ x , , Pu 5f electrons become more delocalized with the typical feature of fewer 5f states below Fermi energy ( E F ) and are expected to be further delocalized in the crystallographically identified Pu–O–F ternary solid compounds, such as PuO 2 F, PuO 2 F 2 , and PuOF 4 .…”