Influence of the energy transfer in a single donor-acceptor pair on the photon distribution functions in its fluorescence

Fluorescence of a single donor-acceptor pair is considered. A donor molecule is described by a three-level energy scheme. It has a 'dark' state, which makes donor fluorescence blinking. An acceptor molecule is described by two-level scheme. Its fluorescence is of continuous type. Strong dependence of the distributions w(N)(D) (T) and W(N)(A) (T) for photons emitted by the donor and the acceptor on the electronic excitation energy transfer rate F between the two molecules is demonstrated. For instance, at F congruent to 1/T(D), where 1/T(D) is the donor fluorescence rate, the fluorescence of the two-level acceptor starts blinking. The photon number distributions at F << 1/T(D) u F >> 1/T(D) are considered as well. (C) 2011 Elsevier B. V. All rights reserved.