The relationship between the g-shift and the local structure for the axial impurity centers in the doped LiNbO3 crystals

The relationship between the g-shift and the local structure of paramagnetic impurity center with axial symmetry is investigated. Spectroscopic data on transitions metal and rare-earth impurities in lithium niobate crystal are used to verify the validity of this method. The distortions around the impurity ions are determined based on the g-shift and compared with experimental data as well as predictions of the superposition model (SPM) and the perturbation methods (PM). The g-shift method yields displacements of impurity ions in good agreement with experimental and SPM or PM predictions. The advantages of the proposed method are discussed.