Theoretical Studies of the Local Structures and EPR Parameters for the Rhombic Cu²⁺ Center in Cu_0.5Zr₂(PO₄)₃ Phosphate

Abstract

The local structure of the rhombic Cu2+ center in Cu0.5Zr2(PO4)3 phosphate is investigated by using the high-order perturbation formulas of electron paramagnetic resonance (EPR) parameters, g-factors gi (i=x, y, z), and hyperfine structure constants Ai for 3d9 ions in rhombically elongated octahedral symmetry. According to the studies, the local axial distortion angle Δα (≈ 5.1°) and the planar bond angle θ (≈ 83.8°) in [CuO6]10- cluster was obtained. The theoretical EPR parameters based on the aforementioned local structure parameters show good agreement with the observed values, and some improvement have been made as compared with the previous studies.