Luminescent Decay of KI:Tl, KBr:Tl, and KCl:Tl

The luminescent decay of single crystals of KI:Tl excited in the $A$, $B$, $C$, and $D$ absorption bands has been investigated over the temperature range 10→300°K. A quantitative description of the decay of luminescence excited in the $A$ band is given. Four of the emission bands have decay times consistent with the Seitz model, but the decay of the 4300-Å band does not agree with this model. Measurements of the luminescent decay of KBr:Tl and KCl:Tl excited in the $A$ absorption band are presented, and the results are compared with those obtained for KI:Tl. The results support the hypothesis that the 3000-Å emission band in KCl:Tl at 10°K is double.