EVANESCENT WAVE-INDUCED FLUORESCENCE STUDY OF RHODAMINE-101 AT DIELECTRIC INTERFACES

Time-integrated and time-resolved evanescent wave-induced fluorescence spectroscopies (EWIFS) have been used to probe the photophysical prop erties of Rhodamine 101 at two solution/solid interfaces. Interaction of Rhodamine 101 with a fused silica surface leads to a reduction in t he molecular fluorescence quantum efficiency in both cases. The fluore scence kinetics of interfacial species are shown to be complex (non-ex ponential), a function of bulk solution concentration, and a function of distance normal to the interface. The application of the maximum en tropy method to the analysis of EWIF decays is presented. Recovered li fetime distributions expose inherent complexity and heterogeneity that is hidden to conventional analysis techniques.