Investigations on the spin Hamiltonian parameters and defect structure for the interstitial Mo5+ centre in TiO2

The spin Hamiltonian parameters, g factors gi (i = x, y, z) and the hyperfine structure constants Ai for the interstitial Mo5+ centre in rutile TiO2 are quantitatively investigated from the perturbation formulas of these parameters for a 4d1 ion in rhombically compressed octahedra. From the studies, the local compression parameter τ′ (≈0.024) and the rhombic distortion angle δϕ′ (≈1.74°) around the impurity Mo5+ are smaller than the host values (≈0.091 and 3.5°). This means that the oxygen octahedron in the impurity centre has less rhombic distortion than that on the host interstitial site due to the Jahn–Teller effect and occupation of the impurity. The above local lattice distortion of the studied impurity centre is also discussed.