Explanations of the g-factors and hyperfine structure constants for CuAlS2: Ti3+ crystals

In this paper, we establish the high-order perturbation formulas of the g-f actors g(parallel to), g(perpendicular to) and hyperfine structure constant s A(parallel to), A(perpendicular to) for 3d(1) ions in the tetragonal MX4 cluster by using a two-spin-orbit (S.O.) coupling parameter model, where no t only the contribution due to the S.O. coupling of the central 3d(1) ion, but also that of ligands are considered. From these formulas, the EPR param eters g(parallel to), g(perpendicular to), A(parallel to) and A(perpendicul ar to) for CuAlS2:T3+ crystal are calculated by using only one adjustable p arameter. All of the calculated results show goad agreement with the observ ed values. Comparing these calculated values with those obtained from the c onventional one-SQ-parameter model, where only the contribution due to the 3d(1) ion is considered, it can be seen that in the cases of ligands having large S.O. coupling parameters, the two-S.O.-parameter model is preferable to the one-S.O.-parameter model in the studies of EPR parameters.