The calculation of zero-field splitting parameters for Fe3+ ions doped in rutile TiO2 crystal by superposition model analysis

► Impurity structure for Fe3+ is firstly investigated through the ZFSPs. ► Both the substitutional and interstitial sites in rutile TiO2 crystal are considered. ► The feasible values of the structural distortions due to Fe3+ ions are determined. ► Satisfactory agreement is achieved between the theoretical and experimental results.