Luminescence decay times of KBr:Ga+

The kinetics of the luminescent decay of KBr: ${\mathrm{Ga}}^{+}$ have been studied from 1.6 to 300 K. Below 45 K, a complex decay consisting of a slow (${\tau }_s$) and fast (${\tau }_f$) time constant is observed for both the $A_T$ and $A_X$ emissions. The temperature dependence of the $A_T$ and $A_X$ decay is explained in terms of the same model: in both $A_T$ and $A_X$ the emitting levels are twofold degenerate with a nondegenerate rap below, in agreement with recent calculations of Bacci et al. and Fukuda et al. From 45 to 55 K, the decay time ${\tau }_s$ of $A_T$ is found to be equal to the rise time of $A_X$. Over the same range of temperature, the $A_X$ emission increases at the expense of the $A_T$ emission. Analysis of these data shows that $A_T$ and $A_X$ relaxed excited states are actually connected by a nonradiative process involving an activation energy $B$.