Abstract

The study of energy transfer processes between optical centers in crystalline cubic materials is reexamined within the conceptual framework of the crystal model. The initial assumption of modest transfer rates is relaxed, thereby correcting the master equation of the crystal model and making it possible to explain the nonexponential behavior of the radiation decay curves from excited states. This study shows that such experimental trends are the result of a purely statistical effect related to the fluctuation in the population of optically active ions in a crystal lattice. The corrected crystal model does not need to invoke migration of excitation processes to explain the fast exponential decay observed in crystals with a high concentration of optical centers. (C) 1997 American Institute of Physics.