Theoretical studies of the EPR g factors and optical spectra for tetragonal Ce3+ centers in CaF2 and SrF2 crystals

By using the irreducible tensor operator technique, the complete energy matrix including the admixture between J = 7/2 and J = 5/2 manifolds and the covalency reduction effect for 4(f1) ion in tetragonal symmetry is established. Based on this, the electron paramagnetic resonance (EPR) g factors for the tetragonal Ce3+ centers in CaF2 and SrF2 crystals are reasonably explained and some levels of the J = 5/2 manifold for these centres are estimated. The results are discussed.