Theoretical studies of the local structure for the trigonal Ti(3+) center in LiF crystal.
Theoretical studies of the local structure for the trigonal Ti(3+) center in LiF crystal.
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DOI：
10.1016/j.saa.2003.12.031
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发表时间：
2004-09
期刊：
影响因子：
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通讯作者：
Shao-yi Wu;Xiu-Ying Gao;Wei-Zi Yan;Wang-he Wei
中科院分区：
文献类型：
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作者：
Shao-yi Wu;Xiu-Ying Gao;Wei-Zi Yan;Wang-he Wei
基于簇方法，利用三角畸变八面体中3d1离子的各向异性g因子g∥和g⊥的微扰公式，从理论上研究了LiF晶体中三角Ti3+中心的局域结构。根据基于各种可能的结构模型的研究，三角Ti3+中心的局部结构可以表征为[TiF3O3]6−团簇（或模型I）。在此模型中，由于 O2− 三角形取代原始 F− 三角形的强静电吸引力，杂质 Ti3+ 预计将取代主体 Li+ 离子，并沿 [111]（或 C3）轴从其规则晶格位置移动约 0.19Å。本工作中获得的上述位移大小与 ENDOR 实验给出的位移大小 (≈0.2–0.3Å) 相当。此外，基于上述结构模型的立方场参数Dq（≈1497cm−1）也与研究系统的实验光谱获得的立方场参数Dq（≈1500cm−1）一致。这项工作中局部结构的理论研究可能有助于理解掺钛 LiF 的光学性质。
The local structure of the trigonal Ti3+center in LiF crystal is theoretically investigated by using the perturbation formulas of the anisotropic g factors g∥and g⊥for a 3d1ion in trigonally distorted octahedra based on the cluster approach. From the studies on the basis of various possible structure models, the local structure of the trigonal Ti3+center may be characterized as [TiF3O3]6−cluster (or model I). In this model, the impurity Ti3+is expected to substitute for the host Li+ion and shift away from its regular lattice site along the [111] (or C3) axis by about 0.19Å due to the strong electrostatic attraction of the O2−triangle replacing the original F−triangle. The magnitude of the above displacement obtained in this work is comparable with that (≈0.2–0.3Å) given by ENDOR experiment. Moreover, the cubic field parameter Dq (≈1497cm−1) based on the above structure model is also in agreement with that (≈1500cm−1) obtained from the experimental optical spectra of the studied system. The theoretical investigations of the local structure in this work may be useful to understand optical properties of Ti-doped LiF.