Theoretical Studies Of ERP Parameters For 3d～1 Ions In Rhombic Tetrahedral And 3d～9 Ions In Rhombic Octahedral Sites

3d~1/3d~9 ions, as the important transition-ions, play a very important role in laser crystals, luminescence crystals, non-line optical crystals, minerals and living matters. Therefore, electron paramagnetic resonance (EPR) spectra of the material including 3d~1/3d~9 ions were widely studied and many experimental data were reported. However, there are not enough theoretical research works about these ions in crystals. For instance, many investigations are based on the simple second- order perturbation formulas, in which only the contributions of the spin- orbit coupling parameters of central 3dn ions to EPR parameters (g factor and hyperfine factor A) are considered (so it is called the one spin- orbit parameter model). But the contribution of spin- orbit coupling effect of ligand to EPR parameters is omitted. Thus, some experimental data were not reasonably explained (for example, when these ions are placed in crystals which have strong covalent bonding or in the condition that the spin- orbit coupling parameters of ligand are comparable with the central mental ions). Consequently, the high- order perturbation formulas based on the two spin- orbit parameter model should be considered and applied to explaining the experimental data. Considering that the EPR parameters are sensitive to the defect structures of impurity centers, the information of the defect structures of the impurity centers in crystals can be obtained from the reasonable analysis...