LiF和AgCl中四角的V2+中心的缺陷结构研究

Investigations on the Defect Structures for the Tetragonal V2+ Centers in LiF and AgCl

  • 摘要: 基于离子簇近似下四角场中3d3离子EPR参量的微扰公式,通过配位场方法对LiF和AgCl中四角V2+中心的缺陷结构和EPR参量进行了理论研究,提出V2+在LiF和AgCl中的缺陷结构模型,即处于杂质离子与C4轴方向上VC间的配体将由于VC的静电排斥作用而朝靠近杂质离子的方向上位移一段距离△Z。根据上述缺陷结构模型得到的EPR参量理论值与实验值吻合较好。

     

    Abstract: The defect structures for the tetragonal V2+ centers in LiF and AgCl are theoretically studied from the perturbation formulas of the Electron Paramagnetic Resonance (EPR) parameters for a 3d3 ion in tetragonal symmetry based on the cluster approach. The structure model proposed in this work suggests that the ligand intervening in the impurity V2+ and the next-nearest-neighbouring cation vacancy (VC) in the C4 axis is expected to suffer an off-center displacement △Z towards the former due to electrostatic repulsion. The theoretical EPR parameters based on the above defect structures show a good agreement with the observed values.

     

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