Wen-Chen Zheng, Qing Zhou, Xiao-Xuan Wu, Yang Mei
Department of Material Science, Sichuan University, Chengdu 610064, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2006 Jan;63(1):126-9. doi: 10.1016/j.saa.2005.04.041.
The EPR parameters (zero-field splitting D and g factors g(parallel), g(perpendicular)) and the first excited state splitting Delta(2E) of the trigonal Cr3+-Vc centers (Vc denotes the cation vacancy in a C3 axis) in Cr3+-doped fluoroperovskites KMgF3, KZnF3, CsCdF3, CsCaF3, RbCdF3 and BaLiF3 are studied from the high-order perturbation formulas. From the studies, the defect structures (characterized by the vacancy-induced displacements Delta x1 of Cr3+ ion and Delta x2 of the three F- ion between Cr3+ and Vc) of these trigonal Cr3+-Vc centers are determined. It is found that the signs of displacements Delta x1 and Delta x2 are consistent with the expectations based on the electrostatic interactions, and the magnitudes of Delta x1 and Delta x2 for Cr3+ in the inverse perovskite BaLiF3 are larger than those for Cr3+ in the classical perovskites. The results are discussed.
利用高阶微扰公式研究了掺Cr³⁺的氟钙钛矿KMgF₃、KZnF₃、CsCdF₃、CsCaF₃、RbCdF₃和BaLiF₃中三角Cr³⁺-Vc中心（Vc表示C₃轴上的阳离子空位）的电子顺磁共振（EPR）参数（零场分裂D和g因子g(平行)、g(垂直)）以及第一激发态分裂Δ(2E)。通过这些研究，确定了这些三角Cr³⁺-Vc中心的缺陷结构（由Cr³⁺离子的空位诱导位移Δx1以及Cr³⁺与Vc之间三个F⁻离子的Δx2表征）。研究发现，位移Δx1和Δx2的符号与基于静电相互作用的预期一致，并且反钙钛矿BaLiF₃中Cr³⁺的Δx1和Δx2的大小大于经典钙钛矿中Cr³⁺的相应值。对结果进行了讨论。
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