Theoretical studies of the g factors and local structures of the Ni3+ centers in Na2Zn(SO4)2·4H2O and K2Zn(SO4)2·6H2O crystals |
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| Authors: | BJ Chen YD Li CD Feng HM Zhang C Yan WB Xiao |
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| Institution: | 1. Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, China;2. Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, China
Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, China |
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| Abstract: | The local structures and the g factors gi (i = x, y, z) for Ni3+ centers in Na2Zn(SO4)2·4H2O (DPPH) and K2Zn(SO4)2·6H2O (PHZS) crystals are theoretically studied by using the perturbation formulas of the g factors for a 3d7 ion with low spin (S = 1/2) in orthorhombically compressed octahedra. In these formulas, the contributions to g factors from both the spin-orbit coupling interactions of the central ion and ligands are taken into account, and the required crystal-field parameters are estimated from the superposition model and the local geometry of the systems. Based on the calculations, the Ni-O bonds are found to suffer the axial compression δz (or Δz) of about 0.111 Å (or 0.036 Å) along the z-axis for Ni3+ centers in DPPH (or PHZS) crystals. Meanwhile, the Ni-O bonds may experience additional planar bond length variation δx (≈0.015 Å) along x- and y-axes for the orthorhombic Ni3+ center in DPPH. The theoretical g factors agree well with the experimental data. The obtained local structural parameters for both Ni3+ centers are discussed. |
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| Keywords: | EPR K2Zn(SO4)2·6H2O (PHZS) local structures Na2Zn(SO4)2·4H2O (DPPH) Ni3+ |
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