Theoretical Investigation of the EPR Spectra and Local Structures for PHZS: Cu²⁺

The electron paramagnetic resonance (EPR) parameters for K₂Zn(SO₄)₂·6H₂O:Cu²⁺, i.e. g factors (g_x, g_y, g_z) and hyperfine structure constants (A_x, A_y, A_z), are theoretically investigated by using the high-order perturbation formulas of these parameters for Cu²⁺ in orthorhombically elongated octahedra. Based on the calculation, the Cu²⁺-H₂O bond-lengths of theCu(H₂O)₆²⁺ cluster in K₂Zn(SO₄)₂·6H₂O crystal are found to be R_x ≈ 0.197 nm, R_y ≈ 0.213 nm, R_z ≈ 0.224 nm, and the mixing coefficients of the ground state wave function parameters areα ≈ 0.978 and β ≈ 0.209, respectively. The calculated EPR parameters show a good agreement with the experimental data.