Investigation of optical spectra and local structure for (CrF6)3− cluster in Cs2NaAlF6:Cr3+ and Cs2NaGaF6:Cr3+ systems

To investigate the local structure of the (CrF6)3− cluster for Cr3+ in Cs2NaAlF6 and Cs2NaGaF6, the unified calculations of the whole EPR, optical spectra are made based on the 120 × 120 complete energy matrices which are constructed on the basis of the complete set of the basis ∣J, MJ〉. The results demonstrate that Cr3+ substitute for the two inequivalent M3+ sites rather than the Na+ or Cs+, which accord with the conclusion of several experiments. Simultaneously, the local structure parameters are determined and the relationship between the structure and the temperature has been discussed.