Influence of restricted geometries on the direct energy transfer

We investigate the direct energy transfer from a donor to acceptors embedded in spaces with restricted geometries. The decay of the donor is expressed in terms of a site density function ρ₀(r) which depends on the position of the donor within the structure. For randomly distributed donors one has to average over their locations. We focus on spherical and cylindrical shapes. The geometrical restrictions manifest themselves in deviations from the known Förster direct transfer behavior.