Intermolecular energy transfer in the presence of dispersing and absorbing media

By making use of the Green-function concept of quantization of the electromagnetic field in Kramers-Kronig consistent media, a rigorous quantum-mechanical derivation of the rate of intermolecular energy transfer in the presence of arbitrarily shaped, dispersing, and absorbing material bodies is given. Applications to bulk material, multislab planar structures, and microspheres are studied. It is shown that when the two molecules are near a planar interface, then surface-guided waves can strongly affect the energy transfer and essentially modify both the (Forster) short-range R - 6 dependence of the transfer rate and the long-range R - 2 dependence, which are typically observed in free space. In particular, enhancement (inhibition) of energy transfer can be accompanied by inhibition (enhancement) of donor decay. Results for four- and five-layered planar structures are given and compared with experimental results. Finally, the energy transfer between two molecules located at diametrically opposite positions outside a microsphere is briefly discussed.