Eu^(3+)掺杂萤石矿物的发光与其晶体结构关系

Relationship between Luminescence and Crystal Structure of Eu^(3+) doped Fluorite

对萤石矿物进行掺杂灼烧．制备了一种新型矿物发光材料萤石：Ｅｕ３＋．根据Ｅｕ３＋的荧光 光谱与局域对称性的关系，结合空间群中等效点系的对称性分析，可以推断该体系中主要存在 ２类发光中心，其格位对称性分别为Ｃ４Ｖ，和Ｃ３Ｖ．Ｅｕ３＋离子进入ＣａＦ２晶格，与Ｃａ２＋离子不等价置换， 由于电荷补偿，Ｅｕ３＋周围常常存在间隙Ｆ 的缺陷机制，间隙 的存在，降低了局域对称性（由Ｏｂ 降低为Ｃ４Ｖ。或Ｃ３Ｖ），打破了宇称选择定则，促进了Ｅｕ３＋离子的发光．

According to the relationship between luminescent properties and local symmetry of Eu3+, to- gether with the site symmetry of symmetrically equivalent points in space group, it can be inferred that there are mainly two kinds of emission centers, which have the C4v or C3v site symmetry respectively, in fluorite:Eu3+ system. The Eu3+ ion requires charge compensation, because it enters the cubic site in a heterovalent substitu- tion for the Ca2+ ion. The charge-compensating defects, such as the predominant interstitial F, influence the local environment of the Eu3+ ions and, in particular, modify the site symmetry. The existence of F rou nd the Eu3+ ion reduces the Oh symmetry to C4v or C3v, which breaks the parity selection rules and promotes the lum- inescence of fluorite:Eu3+ samples.