Theoretical simulation and synchrotron excitation spectra of lanthanide ions in hexafluoroelpasolite lattices

Abstract

Vacuum ultraviolet (VUV) excitation spectra at 10 K have been recorded for the lanthanide ions, Ln3+ ) Nd3+, Ho3+, Tm3+, and Yb3+, situated at octahedral site symmetry in hexafluoroelpasolite Cs2NaLnF6 lattices. The corresponding VUV/UV/visible/near-infrared emission spectra have also been recorded. The 4fN-15d energy levels and 4fN-4fN-15d spectral intensities have been calculated by judicious selection of parameters, without detailed fittings, when employing the M. F. Reid suite of programs. The simulations are in reasonable agreement with experimental data. Some additional spectral features for these systems have been assigned to charge transfer (CT) transitions, and CT emission is reported for the case of Tm3+. A comparison of the results with the spectra of LiYF4:Ln3+ has been included and the major difference lies in the greater crystalfield strengths for Ln3+ in the hexafluoroelpasolite lattices.