The EPR g-factors gi (i = x, y, z) for the interstitial Ti3+ in rutile were theoretically studied from the perturbation formulas of these parameters for a 3d1 ion in rhombically compressed octahedra. The ligand octahedron in the impurity center was found to be less compressed than that on the host interstitial site due to the Jahn-Teller effect. The local compression parameter (≈0.026) and the rhombic distortion angle δφ′ (≈0.7°) around the impurity Ti 3+ were smaller than the host values (≈0.091 and 3.5°). The theoretical g factors based on the above local structural parameters were in good agreement with the experimental data. In addition, the g-factors for a tetragonal interstitial Ti3+ center were also reasonably interpreted.

Investigations on the Local Structure and g Factors for the Interstitial Ti3+ in TiO2. Wei, L.H., Wu, S.Y., Zhang, Z.H., Wang, X.F., Hu, Y.X.: Pramana, 2008, 71[1], 167-73