Comments on Random Walk and Diffusion as Models for Exciton Migration

It has been shown that exciton diffusion cannot explain the time dependence of host-sensitized energy transfer in doped organic crystals. It is claimed in a recent publication that formulating exciton migration as a random-walk problem eliminates any discrepancies in the observed and predicted time dependences of the energy transfer. In this paper we show that the two models for exciton migration give exactly the same theoretical predictions, and the anomalous time dependence remains unexplained.