Abstract—

The electron paramagnetic resonance (EPR) parameters (g-factors g_//, g_⊥ and the hyperfine structure constants A_//, A_⊥) and local structure are theoretically investigated for Cu²⁺-doped oxyfluoroborate (20Li₂O–10Li₂F₂–70B₂O₃) glasses based on the three-order perturbation formulas for an octahedral 3d⁹ cluster with tetragonal elongation distortion. In these formulas, the ligand orbital and spin-orbit coupling contributions are considered on the basis of the cluster approach due to moderate covalency. The tetragonal crystal-field parameters are determined by the superposition model. According to our calculations, the impurity-ligand bonding length parallel and perpendicular to the C₄ axis of [CuO₆]^10– cluster are found to be, respectively, R_// ≈ 2.133 Å and R_⊥≈ 1.947 Å, due to Jahn–Teller effect. Based on these local structure data, the calculated g-factors are in good agreement with the observations. The signs of A_// and A_⊥ for the Cu²⁺ center are suggested in the discussion

中文翻译：

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氟硼酸玻璃中Cu 2+的局部结构和EPR参数的研究

摘要-

电子顺磁共振（EPR）的参数（克-因子克_//，克_⊥和超精细结构常数甲_//，甲_⊥）和局部结构的理论研究为铜²⁺掺杂oxyfluoroborate（20LI ₂ -O-10Li ₂ F ₂ –70B ₂ O ₃）玻璃基于八面体3 d ⁹的三阶摄动公式簇具有四边形伸长变形。在这些公式中，由于具有中等共价性，因此基于聚类方法考虑了配体轨道和自旋轨道的耦合作用。四方晶场参数由叠加模型确定。根据我们的计算，杂质-配体键合长度平行和垂直于C ₄的轴[CuO的₆ ] ^10-簇被发现是，分别ř _// ≈2.133埃和- [R _⊥ ≈1.947埃，由于雅恩–讲者效应。基于这些局部结构数据，计算出的g因子与观测值非常吻合。A的迹象_//和一个_⊥对于Cu ²⁺中心的建议的讨论