Theoretical Studies Of The Spin Hamiltonian Parameters For 3d～1/3d～9 Ions In Rhombic Crystals

Spin-Hamiltonian Theory is a powerful tool to study the paramagnetic properties of transition metal ions and rare earth ions in crystals, and then to understand further the local structures of these paramagnetic centers in crystals. Experimentally, spin- Hamiltonian parameters can be measured by electron paramagnetic resonance (EPR) spectra. Based on this, the information about spin energy level splitting of paramagnetic ions and hence the local environment where paramagnetic ions located can be obtained. Therefore, it's a feasible way to know the defect structure information in the doped crystals. Microcosmically, spin-Hamiltonian parameters can be calculated and studied by microcosmic spin-Hamiltonian theory. An important way of spin-Hamiltonian theory is perturbation method.Until now, the research about electron paramagnetic resonance (EPR) spectra of 3d~1/3d~9 ions in rhombic crystals has not been enough. This is shown in the following content: in the conventional crystal-field theory, the perturbation formulas just considered the spin-orbit (SO) coupling parameters of central 3d~1/3d~9 ions contributing to EPR (g factors and the hyperfine structure constant A factors) parameters (namely single spin-orbit parameter model). But, when 3dn (including 3d~1/3d~9) system has a strong covalent character or when the SO coupling parameters of ligand can compare with the central 3d~1/3d~9 ions, we should also consider the contribution of ligands'SO coupling parameters to EPR parameters, and accordingly...