SrCl_2∶Ag^(2+)晶体局部结构及电子顺磁共振参量的理论研究  

Theoretical Studies on the Local Structure and the EPR Parameters of SrCl_2∶Ag^(2+)

作　　者：林季资[1] 肖沛[1] 赵越[1] 张宝芳[1] 杨圆[1] 

机构地区：[1]江苏科技大学(张家港)基础教学部,张家港215600

出　　处：《人工晶体学报》2016年第1期200-204,共5页Journal of Synthetic Crystals

基　　金：江苏省高校自然科学研究面上项目(15KJD140003)

摘　　要：基于离子簇模型,采用d^9离子在四角伸长八面体对称中电子顺磁共振(EPR)参量的高阶微扰公式,计算了SrCl_2中四角Ag^(2+)中心的EPR参量(g因子g_(//),g_⊥和超精细结构常数A因子A_(//),A_⊥)。由于体系的共价性及配体Cl^-较大的旋轨耦合系数,在这些公式中同时考虑了配体轨道及旋轨耦合作用对EPR参量的贡献。公式里的能级分裂由重叠模型和杂质中心的局部结构确定。研究发现,掺杂后由于尺寸失配,杂质Ag^(2+)沿着C_4轴有一个很大的非中心位移,到最近邻的Cl^-平面距离约为0.060 nm。计算所得的EPR理论值与与实验值符合的很好。The local structure and the EPR parameters g factors g_(//) and g_⊥ and the hyperfine structure constants A_(//) and A_⊥ for the tetragonal Ag^(2+) center in SrCl_2 are theoretically studied from the high-order perturbation formulas of these parameters for a d^9 ion in tetragonal symmetry(elongated octahedron).In these formulas,the ligand orbital and spin-orbit coupling contributions are included in view of the large spin-orbit parameter of the ligand Cl^- and covalence effect,and the energy separations are determined from the superposition model and the local structure of the impurity center.Based on the studies,the impurity Ag^(2+) is found to be located at a distance of about 0.060 nm from the nearest chlorine plane.The theoretical EPR parameters show good agreement with the experimental data.

关 键 词：电子顺磁共振(EPR) 重叠模型 Ag2+ SR CL2 

分 类 号：O737[理学—晶体学]