Thermoluminescence due to simultaneous recombination of two electrons into two-hole centers

A model describing the possibility of simultaneous recombination of two electrons into two-hole recombination centers yielding thermoluminescence (TL) is presented. This follows previous reports on such transitions in some other solid-state phenomena. The simulated results may explain some unusual TL effects. These include the occurrence of very narrow peaks which results in the evaluation of very high effective activation energies and exceedingly high effective frequency factors, sometimes reported in the literature. The model can also explain the more-than-quadratic dose dependence of TL. Other effects are peaks with symmetry factors smaller than that of first-order peaks or intermediate between that of first and of second order. Another result of the simulations is the possibility of first-order-like peaks that shift with the excitation dose. Finally, the possibility of a dose-rate effect is also seen in the results of the simulations. In addition to the numerical simulations, limited to a small number of sets of parameters, an analytical treatment with some approximations has been developed. For a certain set of parameters and rather low excitation dose, the agreement between the results of the simulation and theory has been very good.