Role of diffusion in excitation energy transfer: a time-resolved study

Excitation energy transfer between acriflavine and erythrosin B dyes in sol utions of two different viscosities has been studied. For low acceptor conc entrations decay is exponential whereas for high acceptor concentrations it fits with Forster function for energy transfer. The observed diffusion coe fficients are higher than even the sum of diffusion cofficient for translat ional diffusion and energy migration for immobile donors. This has been att ributed to the increased donor-donor transport in the presence of translati onal diffusion. It is interesting to note that our experimental results are in complete agreement with the theoretical results of one of the recent ge neral models for energy transfer and migration (C) 2000 Elsevier Science B. V. All rights reserved.