Non-radiative energy transfer between impurity ions in crystals: configuration mixing

In this work, the non-radiative energy transfer mechanism between a pair of distinct dopant ions in a monocrystalline matrix is reviewed, the transfer mechanism is contemplated as a result of the configuration mixing of the e nergy levels of the subsystem donor-acceptor couple. When this resonance is considerable, a strong mixing takes place between two of the wave function s of the involved ions, and this mixing results in an increased value of th e probability of non-radiative energy transfer. On the other hand, Dexter's classical theory for non-radiative energy transfer can be applied as a lim iting case when the energy resonance is neglected. The rate of non-radiativ e energy transfer has been calculated for various systems where this proces s has been observed, finding that, for specific energy levels of the subsys tem pair the calculated non-radiative excitation transfer is in close agree ment with the experimentally determined rate. (C) 1999 Elsevier Science B.V . All rights reserved.