SPECTRAL-ANALYSIS OF THE FLUORESCENCE QUENCHING KINETICS IN MICELLES WITH PROBE MIGRATION

The fluorescence quenching kinetics in monodisperse micelles consideri ng intermicellar probe migration has been studied. Decay parameters ob tained via eigenfunction expansion are correlated with the lifetime di stribution and the rules of the exponential series method (ESM) applie d to micellar kinetics. In a system where interacting micelles allow t he excited probe to migrate between aggregates with a rate constant of the same order of that of intramicellar quenching, the principal eige nvalues will follow approximately the optimization constrain of the ES M method in which the inverse of the lifetimes is a linear function of the occupancy number j = 0,1,2,.... However, the normalized amplitude s of the discrete set of exponential decay terms are no longer Poisson distributed, although the model for quencher distribution in the equi librium state is assumed to follow a Poisson law. This indicates that the distribution pattern recovered using the ESM cannot be uniquely co rrelated to the quencher occupancy statistics when probe migration occ urs. (C) 1997 Elsevier Science B.V.