ON THE RbBr:Cu⁺ FLUORESCENCE

The fluorescence of Cu⁺ in RbBr was investigated in the temperature range 20-300 K, by recording both emission and excitation spectra and by performing accurate lifetime and quantum yield measurements. The de-excitation mechanism has been interpreted in terms of the traditional Pedrini model. Nevertheless, a change of the compression conditions for Cu⁺ at low temperature was observed, which implies two temperature regions (above and below 40 K) for the decay parameters. This occurrence is related not only to off-centre configuration but also to a very low value for the Cu⁺ radius when compared to the Rb⁺ one in RbBr.