Temperature dependence of anomalous luminescence decay: Theory and experiment

The anomalous decay of slow emission in impurity-doped alkali halides is studied both experimentally and theoretically. Experiments systematically examine the decay of luminescence in Pb²⁺-doped KBr for temperatures from 6 to 110 K and for times from 40μs to 40 ms. Theoretical methods, previously used to explain the anomaly at low temperature, are extended to deal with phonon-induced transitions and other high-temperature phenomena. The significant ansatz of this and the previous work is slow (ms scale) relaxation of the lattice. This ansatz continues to allow successful theoretical fitting of the data.