Figure 1.

Illustration of the various ways in which an excited donor can lose its electronic excitations when associated with acceptors. Significance of the symbols: i and j, counting indices for donors and acceptors, respectively; Γ with various superscripts, rate constants of deexcitation; superscript r, a radiative process; superscript nr denotes a nonradiative process other than transfer to the acceptor (such as internal conversion); superscript FRET denotes a Förster resonance energy transfer from D to A.