EFFECTS OF STATIC QUENCHING AND LIGHT-PULSE INTENSITY ON THE TIME-DEPENDENT FLUORESCENCE QUENCHING KINETICS

초록

By employing the general kinetic theory proposed recently for treating the diffusion-influenced fluorescence quenching, we investigate the nonequilibrium dynamic effect of the complex formation reaction between the ground state fluorophor and quencher molecules on the time-resolved fluorescence decay curve. We find that as the complex formation constant K(eq) becomes larger the time at which the fluorescence intensity becomes maximum shifts to a shorter time. In contrast, conventional theory predicts that the scaled fluorescence decay curve is invariant under the change in the K(eq) value. This observation suggests a possibility of determining the magnitude of K(eq) from the time-resolved fluorescence decay data as well as from the curvature of a Stem-Volmer curve. We also investigate the effects of various kinetic factors such as the intensity and shape of the light pulse, the magnitude of quencher concentration, and the presence of an attractive Coulomb force or a long-range energy transfer mechanism. We find that the conventional theory may fail in some experimental situations where repeated excitation of fluorophor molecules is possible.

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