In order to check whether the parametrized crystal field approach was efficient in the analysis of an EPR powder spectrum defects of known geometry were studied as if they were unknown. The g-tensor of an interstitial V4+ ion in a single crystal of rutile TiO2 could be interpreted without ambiguity, and the optimized parameters compare well with their theoretical values. For an interstitial Ti3+ ion, two solutions were found: both of them correspond to interstitial positions, but they differed in the principal axis orientation.

g Tensor of Transition Ions in a Crystalline Matrix: Interstitial V(IV) and Ti(III) in Rutile TiO2. Boudeville, Y., de Montgolfier, P.: Chemical Physics Letters, 1975, 30[3], 469-71