Abstract The clustering of trivalent lanthanide-doped fluorite was divided into four stages. Characters of the first three stage discrete clusters were studied by the density functional theory (DFT) based first principles calculation in the work. The results revealed the relative stabilities of first stage C4v and C3v were intimately correlated with that of the second and third stage clusters. The more stable C4v with interstitial Fi- at the nearest site would stabilize the second cubic sublattice centers and C3v with Fi- at next nearest site for the third square antiprism clusters. The lattice mismatch and projected density of states (pDOS) results indicated that coupling of electrostatic, strain, bonding and hybridization among Fi-, RE3+ and surrounded lattice anions controlled the site occupation and the correlations. The clusters and clustering features could be modulated and utilized to tune up- and down-conversion photoluminescence for designing of new lanthanide-doped fluorite materials.

中文翻译：

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RE3+ (RE=Y, La ∼ Lu) 在 MF2 (M=Ca, Sr, Ba) 萤石中的缺陷聚集

摘要 三价镧系元素掺杂萤石的成簇分为四个阶段。在工作中通过基于密度泛函理论（DFT）的第一性原理计算研究了前三级离散簇的特征。结果表明，第一阶段 C4v 和 C3v 的相对稳定性与第二和第三阶段簇的相对稳定性密切相关。对于第三个方形反棱镜簇，在最近的位置具有间隙 Fi-的更稳定的 C4v 将稳定第二个立方亚晶格中心和具有 Fi-的 C3v 在下一个最近的位置。晶格失配和投影态密度 (pDOS) 结果表明 Fi-、RE3+ 和包围的晶格阴离子之间的静电、应变、键合和杂化的耦合控制了位点占据和相关性。