Theoretical studies of the local structure and EPR parameters for Cu2+ centers in disodium malonate trihydrate single crystal

The electron paramagnetic resonance (EPR) parameters (g factors gxx, gyy, gzz and hyperfine structure constants Axx, Ayy, Azz) of the two Cu2+ centers in disodium malonate trihydrate (DSMT) single crystal are theoretically interpreted using the high order perturbation formulas of these parameters for a 3d9 ions in rhombically elongated octahedra. In the calculation, the rhombic crystal-field parameters are determined from the superposition model and the admixture of d  -orbitals in the ground state wave function are taking account, the results show that although the admixture of the |dz2〉 state to the ground state wave function is small, it should not be neglected in calculations of the EPR parameters. The theoretical EPR parameters show good agreement with the observed values. The results are discussed.