DHMS中掺杂Cu2+电子顺磁共振参量及局部结构

Theoretical Investigation of the Electron Paramagnetic Resonance Parameters and Local Structures for DHMS: Cu2+

  • 摘要: 基于晶体场模型,利用3d9离子斜方(C4v)伸长八面体对称EPR参量的高阶微扰公式,计算了(NH4)2Mg(SO4)2·6H2O:Cu2+的g因子gii和超精细结构常数Aii。公式中晶场参量由重叠模型确定,计算中考虑了d轨道基态波函数的混合。研究结果表明,晶体(NH4)2Mg(SO4)2·6H2O中络离子Cu(H2O)62+的Cu2+-H2O键长Rx约为0.187 2 nm,Ry约为0.203 3 nm,Rz约为0.229 2 nm;中心金属离子基态波函数混合系数αβ分别为0.995和0.099 9。所得EPR参量理论计算与实验符合很好,并对上述结果进行了讨论。

     

    Abstract: Based on the crystal field theory, the anisotropic g factors gii and the hyperfine structure constants Aii for (NH4)2Mg(SO4)2·6H2O:Cu2+ are theoretically investigated by using the high-order perturbation formulas of these electron paramagnetic resonance (EPR) parameters for a 3d9 ion in rhombically (C4v) elongated octahedra. In the calculated formulas, the crystal field parameters are set up from the superposition model and the admixture of d-orbitals in the ground state wave function is taken into account. According to the calculations, the local structure values Cu(H2O)62+ clustering in (NH4)2Mg(SO4)2·6H2O crystal are: Rx≈0.1872 nm, Ry≈0.2033 nm, Rz≈0.2292 nm; and the mixing coefficients of the ground state wave function parameters α and β are 0.995 and 0.0999, respectively. The calculated results show good agreement with the experimental data, and the reasonableness of these results is discussed.

     

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