Optical properties of Mn3+ ions in Cs2NaAlF6 and Cs2NaGaF6 single crystals

The optical properties of Mn3+ ions in the elpasolites Cs2NaGaF6 and Cs2NaAlF6 have been investigated by absorption spectroscopy at 4.2 K. The absorption spectra are dominated by the spin-allowed 5E → 5T2 transition and the transition between the two Jahn-Teller components of the 5E level. The crystal-field parameter Dq was determined and a low crystal-field situation was established for both Mn3+-doped fluorides. The Jahn-Teller stabilization energies of the 5E and 5T2 levels were calculated and the obtained values shown a strong Jahn-Teller splitting in the 5E ground state.