Electronic spectra and crystal field analysis of TmF₆ ^{3 -}

The 10 K electronic absorption spectrum of Cs₂NaTmF₆ together with the 355 nm and 455 nm excited luminescence spectra of Cs₂NaYF₆:Tm³⁺ (1 and 10 at.% Tm³⁺) have been recorded and assigned in detail. Vibrational structure in the sidebands of the electronic transitions is analogous to that in the spectra of the hexachloroelpasolite systems except that the phonon dispersion is greater. The resulting 4f¹² energy level dataset has been analyzed by a crystal field model including the configuration interaction with the ligand to metal charge transfer configuration. The previously published spectra of Rb₂NaTmF₆ and Rb₂NaYF₆:Tm³⁺ have been reinterpreted and shown to be consistent with the present results. © 2007 Elsevier B.V. All rights reserved.