EPR g factors and defect structures for V4+ and Cr5+ in the rutile-type crystals

• We established formulas for EPRg for GeO2:V4+, TiO2:V4+ and TiO2:Cr5+.
• The calculation and experimental values are very close to each other.
• The ligand octahedron is more compressed because of the Jahn–Teller effect.

The g-factor formulas for V4+ and Cr5+ ions in the rutile-type crystals are deduced from Jahn-Teller effect and contributions of the charge transfer levels. The tetragonal distortions ΔR = −0.0045, −0.0045 and −0.0067 nm, and Δθ = 0°, −0.001° and 0°, for GeO2:V4+, TiO2:V4+ and TiO2:Cr5+, respectively. The calculations of the g-factors agree well with the experimental values. The contributions of the charge transfer levels to g factors increase with the increasing valence state. It must be taken into account in the precise calculations of g factors for the high valence state d1 ions in crystals.