标题： 理论研究Cu$^{2+}$中心在Cd$_{2}$(NH$_{4}$)$_{2}$(SO$_{4}$)$_{3}$单晶中的局部结构和EPR参数 显示英文标题

标题： Theoretical studies of the local structures and EPR parameters for Cu$^{2+}$ center in Cd$_{2}$(NH$_{4}$)$_{2}$(SO$_{4}$)$_{3}$ single crystal

摘要： 电子顺磁共振（EPR）参数（$g$因子$g_{i}$和超精细结构常数${{A}}_{{i}}$，${i} = {x}, {y}, {z}$）是通过使用在菱形（{D}$_{2h}$ ）拉长八面体中的$3{d}^{9}$离子的微扰公式来解释的。 在计算公式中，晶体场参数是从超叠加模型建立的，并考虑了基态波函数中$d$轨道的混合对 Cu$^{2+}$离子的EPR参数的贡献。 根据计算，获得了杂质Cu$^{2+}$中心在Cd$_{2}$(NH$_{4}$)$_{2}$(SO$_{4}$)$_{3}$ (CAS) 晶体中的局部结构参数 （即，${R}_{{x}}\approx 2.05$ {\AA } ，${R}_{{y}} \approx 1.91$ {\AA } ， ${R}_{{z}} \approx 2.32$ {\AA } ）。 基于上述Cu$^{2+}$-O$^{2-}$键长的理论EPR参数在CAS晶体中与观测值有很好的一致性。 结果被讨论。 显示英文摘要

摘要： The electron paramagnetic resonance (EPR) parameters ($g$ factors $g_{i}$ and the hyperfine structure constants ${{A}}_{{i}}$, ${i} = {x}, {y}, {z}$) are interpreted by using the perturbation formulae for a $3{d}^{9}$ ion in rhombically ({D}$_{2h}$) elongated octahedra. In the calculated formulae, the crystal field parameters are set up from the superposition model, and the contribution to the EPR parameters from the admixture of $d$-orbitals in the ground state wave function of the Cu$^{2+}$ ion was taken into account. Based on the calculation, local structural parameters of the impurity Cu$^{2+}$ center in Cd$_{2}$(NH$_{4}$)$_{2}$(SO$_{4}$)$_{3}$ (CAS) crystal were obtained (i.e., ${R}_{{x}}\approx 2.05$ {\AA}, ${R}_{{y}} \approx 1.91$ {\AA}, ${R}_{{z}} \approx 2.32$ {\AA}). The theoretical EPR parameters based on the above Cu$^{2+}$-O$^{2-}$ bond lengths in CAS crystal show a good agreement with the observed values. The results are discussed.