Luminescence spectra and relaxation processes of ReBr 2–6 in cubic crystals
Abstract
The Γ8, Γ7(2T2g, t32g,)→Γ8(4A2g, t32g) luminescence spectra and decay curves for the ReBr2–6 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 ReBr2–6 ion are strongly coupled to the corresponding internal modes of the SnBr2–6 ion. This cannot occur in the chloride lattices but in this case the ν6 and ν4 ReBr2–6 modes couple to the transverse and longitudinal optic modes of the lattice.