Thermodynamic stability of PuO2surfaces: Influence of electronic correlations

Abstract

In this article, we performed accurate ab initio calculations in order to address the influence of electronic correlations on the surface stability of PuO 2 . Various terminations of the (100), (110), and (111) orientations were considered, among which some are polar. Standard density-functional theory (DFT), which is known to provide a poor description of the electronic structure of plutonium oxides, predicts an unexpected stabilization of the polar uncompensated terminations O 2 -(111) and Pu-(111). We show that this shortcoming is no longer observed when the more relevant PBE + U framework is used. The so-obtained better description of the strong electronic correlations leads to a destabilization of these two terminations, leaving only one stable surface, the O-(111) stoichiometric one. Beyond the surface stability, we show that the electronic structure is strongly affected since the PBE + U approach is able to render only a proper insulating behavior. This should have a strong effect on the surface reactivity of these systems and prevent the use of standard DFT.

Magnetic structure of UO2and NpO2by first-principle methods

“…A limited number of publications have investigated noncollinear contributions, [48][49][50] and collinear 1k AFM order is often used to model the electronic structure. 9,34,42,49,[51][52][53][54][55][56][57][58][59][60][61][62][63] The inclusion of spin-orbit interactions (SOI) 14 is often ignored, 34,46,48,[60][61][62]64 although a number of investigations have highlighted its importance. 33,48 This is mainly due to the computational cost.…”

The environmental dependence of redox energetics of PuO2 and α-Pu2O3: A quantitative solution from

“…The effective modification of pure DFT by LDA/GGA+U formalisms has been confirmed widely in studies of PuO 2 [27][28][29][30][31][32][33][34][35], which have reported the AFM-insulator ground state of…”

Water on Actinide Dioxide Surfaces: A Review of Recent Progress

“…Calculated surface energies of AnO 2 have been reported in several papers, particularly for ThO 2 , UO 2 , and PuO 2 . Tables 1-3 summarize the surface energies for the low indexed (111), (110), and (100) surfaces, comparing the different reports that employed DFT and those that relied on other classical models [25][26][27][28][29][30][31][32][33]. It is seen that DFT calculations give rise to smaller surface energies than the classical models for ThO 2 , UO 2 , and PuO 2 surfaces.…”