Luminescence spectra and relaxation processes of ReBr 2–6 in cubic crystals

Abstract

The Γ₈, Γ₇(²T_2g, t³₂g,)→Γ₈(⁴A_2g, t³_2g) luminescence spectra and decay curves for the ReBr^2–₆ ion in Rb₂SnBr₆, Cs₂SnBr₆, K₂SnCl₆ and K₂PtCl₆ have been measured over the temperature range 5–300 K with a range of excitation wavelengths. A scheme for the observed complex relaxation processes is proposed. For the two bromide lattices the vibronic spectra show that the internal vibrational modes of the ReBr^2–₆ ion are strongly coupled to the corresponding internal modes of the SnBr^2–₆ ion. This cannot occur in the chloride lattices but in this case the ν₆ and ν₄ ReBr^2–₆ modes couple to the transverse and longitudinal optic modes of the lattice.