CEA, DEN, Service de Recherches de Métallurgie Physique , Université Paris-Saclay , F-91191 Gif-sur-Yvette , France.
SPMS, CNRS, Centrale Supélec , Université Paris-Saclay , F-91190 Gif-sur-Yvette , France.
Inorg Chem. 2019 Oct 7;58(19):12678-12688. doi: 10.1021/acs.inorgchem.9b01483. Epub 2019 Sep 10.
We use the Second Moment Tight Binding with charge eQuilibration (SMTB-Q) advanced empirical potential to study clusters of oxygen interstitials in hyperstoichiometric UO. This potential reproduces the trends obtained from density functional theory calculations. We exhibit a new form of cuboctahedron that proves to be the most stable oxygen cluster in UO. Considering different types of random arrangements of these clusters, we reproduce the fact that UO and UO are the only two stable phases at low temperature in their composition range. Focusing on UO at low temperature, we obtain a model for the α-UO phase, which exhibits the experimental 3 space group. We present the results of the original neutron diffraction experiments measured on UO at 1.5 K and perform a Rietveld refinement of the calculated UO structure, which enables us to propose a complete description of the α-UO phase.
我们使用带电荷平衡的二阶紧束缚(SMTB-Q)先进经验势来研究富氧UO 中的氧间隙原子团簇。该势能够重现从密度泛函理论计算中得到的趋势。我们展示了一种新的立方八面体形式,它被证明是 UO 中最稳定的氧团簇。考虑到这些团簇的不同随机排列类型,我们重现了在其组成范围内 UO 和 UO 是低温下仅有的两种稳定相的事实。在低温下关注 UO,我们得到了 α-UO 相的模型,该模型表现出实验的 3 空间群。我们呈现了在 1.5 K 下对 UO 进行的原始中子衍射实验的结果,并对计算出的 UO 结构进行了 Rietveld 精修,这使我们能够提出对 α-UO 相的完整描述。