Contribution of one-phonon processes to the electronic energy transfer in disordered solids

The contribution of nonresonant one phonon processes to the ensemble averaged probability that an initially excited donor is excited at a later time t has been evaluated. A distribution of energy differences between the electronic levels involved in the transfer process is explicitly allowed in this model, which leads to a dependence of the ensemble-averaged probability on the initial distribution of donor ions and on the temperature. In order to perform such an ensemble average, the truncated cumulant expansion method has been used, which has been shown to give an accurate value for this quantity in the experimental time scale. We find that two temporal regimes emerge from the calculation, which are characterized by very distinct temporal, temperature, and initially excited donor ion energy difference dependencies. © 2000 The American Physical Society.