Thermal quenching of characteristic luminescence. II

A model proposed earlier to explain the dependence of the quenching temperature (T_q) of a given luminescent center on the host lattice is extended to luminescent centers bearing a formally effective charge. Predictions from this model are compared with experimental data. The agreement is satisfactory. It turns out that effectively charged centers with charge-transfer excitation (e.g., Eu³⁺, WO^2?₄) do not have a high value of T_q, whereas those with Rydberg excitation (e.g., Tl⁺, Tb³⁺) can have a high value of T_q, especially if the host lattice is rigid.