Abstract

Pyrene fluorescence of a molecular donor-acceptor nanoaggregate induced by infrared (IR) radiation with λ =16 - 18 μm considered.We assume that this nanoaggregate consists of two molecules, exchanging energy by dipole-dipole interaction. The energy acceptor is an aromatic molecule. The other molecule, the energy donor, is assumed to contain a substructure C_nH_2n which serves as antenna for IR radiation. The antenna can accumulate collective vibrational excitations and transmit them to the acceptor molecule. Acceptor fluorescence is possible if the amount of transmitted energy is equal to the energy of its excited state in the visible part of the absorption spectrum. We analyse the fluorescence of a nanoaggregate consisting of a donor with a C₅H₁₀ substructure and pyrene molecules or pyrene dimers as acceptors. A method is proposed for determination of the ‘critical micelle concentration’ (CMC), i. e. concentration of a dissolved polymer, for which the polymer molecules are beginning to aggregate.