Thermal quenching of chromium photoluminescence in ordered perovskites. II. Theoretical models

Several theoretical models for thermal quenching of chromium photoluminescence in ordered perovskites, whose parameters are severely constrained by empirical spectral information, are compared. Models based on linear coupling to modes of $a_{1g}$ symmetry fail by 6–8 orders of magnitude to explain the observed radiationless-transition rate. A new model, which combines linear coupling to an $a_{1g}$ mode with quadratic coupling to a $t_{2g}$ mode, is in order-of-magnitude agreement with experiment.