Off-centre effects in the triplet relaxed excited state of Ga+ centres in CsBr : Ga crystal

Spectra, polarization and decay kinetics of the triplet and singlet emission of Ga + centres in CsBr:Ga crystals have been studied in the temperature range of 0.1 to 400K. It has been found that the triplet Ax and AT emission bands coincide. Two slow components have been observed in the decay kinetics of each emission at T< 1.5 K and explained by the tunnel splitting of the metastable minima of the corresponding triplet relaxed excited state. It points to the off-centre displacement of a Ga + ion from a crystal lattice site both in the tetragonal (T) and in the trigonal (X) Jahn-Teller minima.