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

The 360 and 458 nm excited luminescence spectra of single crystals of Rb2Na Y0.95Tm0.05F6 have been measured at temperatures down to 15 K. The D-1(2) - -> F-3(4), and (1)G(4) --> F-3(4), H-3(5) transitions each show extensive v ibronic structure which has been analysed in detail. In addition, under 458 nm excitation, several transitions from the D-1(2) state located at 28050 cm(-1) are observed following up-conversion. The H-3(6) --> D-1(2) transiti on has been located in absorption and its vibronic structure analysed. A fu rther eight electronic states of the TmF63- ion have been located. The crys tal field splittings are substantially larger than for the TmCl63- and TmBr 63- ions. (C) 1999 Elsevier Science B.V. All rights reserved.