Synchrotron excitation, emission and theoretical simulation of lanthanide ions in hexachloroelpasolite crystals

Emission and excitation spectra of Cs2NaLnCl6 (Ln = Y, Eu, Gd, Er, Yb), Cs2NaYCl6:Ce and Cs2NaYCl6:Tm have been recorded using synchrotron radiation. With the possible exception of the case for Ce3+, no 5d →4f transitions are observed and the emission spectra are entirely assigned to 4f→4f intraconfigurational transitions of Ln3+ in LnCl3− 6 and impurity species. The excitation spectra comprise intraconfigurational, charge transfer and band-to-band transitions. Trace impurities of oxy-species or of other lanthanide ions have a profound effect upon the spectra. The 4f–5d absorption spectra have been simulated by employing the suite of programs of Professor M F Reid and the results have been included together with the experimental spectra.