Luminescence and electronic absorption spectra of Rb2NaY0.95Tm0.05F6

The 360 and 458 nm excited luminescence spectra of single crystals of Rb2NaY0.95Tm0.05F6 have been measured at temperatures down to 15 K. The 1D2→3F4, and 1G4→3F4, 3H5 transitions each show extensive vibronic structure which has been analysed in detail. In addition, under 458 nm excitation, several transitions from the 1D2 state located at 28050 cm−1 are observed following up-conversion. The 3H6→1D2 transition has been located in absorption and its vibronic structure analysed. A further eight electronic states of the TmF63− ion have been located. The crystal field splittings are substantially larger than for the TmCl63− and TmBr63− ions.