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arXiv · 0911.0256

First-principles LDA+U and GGA+U study of neptunium dioxide

Baotian Wang·Hongliang Shi·Weidong Li·Ping Zhang
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Abstract

We have performed a systematic first-principles investigation to calculate the electronic structures, mechanical properties, and phonon dispersion curves of NpO$_{2}$. The local density approximation$+U$ and the generalized gradient approximation$+U$ formalisms have been used to account for the strong on-site Coulomb repulsion among the localized Np $5f$ electrons. By choosing the Hubbard \emph{U} parameter around 4 eV, the orbital occupancy characters of Np 5\emph{f} and O 2\emph{p} are in good agreement with recent experiments [J. Nucl. Mater. \textbf{389}, 470 (2009)]. Comparing with our previous study of ThO$_{2}$, we note that stronger covalency exists in NpO$_{2}$ due to the more localization behavior of 5\emph{f} electrons of Np in line with the localization-delocalization trend exhibited by the actinides series.

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Baotian Wang, Hongliang Shi, Weidong Li, Ping Zhang. 2009-11-02. First-principles LDA+U and GGA+U study of neptunium dioxide. https://doi.org/10.1103/physrevb.81.045119

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