Investigation of the EPR parameters of the rhombic Cu²⁺center in (NH₄)₂Mg(SO₄)₂·6H₂O single crystal

Abstract

The electron paramagnetic resonance (EPR) parameters (g factors g x , g y , g z and hyperfine structure constants A x , A y , A z ) for Cu 2+ in (NH 4 ) 2 Mg(SO 4 ) 2 ·6H 2 O (DHMS) crystal are theoretically investigated using the high-order perturbation formulas of these parameters. In the calculations, the ligand orbital and spin-orbit coupling for the impurity Cu 2+ are taken into account; the required crystal-field parameters are estimated from the superposition model which enables correlation of the crystal-field parameters and hence the EPR parameters with the local structure of the impurity center. The ligand orbital and the spinorbit coupling contributions are included on the basis of the cluster approach. Based on the calculation, the theoretical EPR parameters show good agreement with the observed values. The results are discussed.

Theoretical studies of the g factors and local structures of the Ni3+ centers in Na2Zn(SO4)2·4H2O and K2Zn(SO4)2·6H2O crystals

“…The studied Ni 3+ centers in DPPH and PHZS crystals are different from other TM impurity (e.g., Mn 2+ , Cr 3+ , and Fe 3+ [46][47][48] ) centers in the same crystals, with the nondegenerated ground state in the absence of the Jahn-Teller effect. In addition, when the impurity Cu 2+ enters Tutton salts, [14,15,[49][50][51][52] it may also occupy the host Zn 2+ site, but usually presents elongated octahedra instead of the compressed octahedra in the studied systems.…”