DISTANCE-DEPENDENT QUENCHING OF ANTHRACENE FLUORESCENCE BY N,N-DIETHYLANILINE OBSERVED BY FREQUENCY-DOMAIN FLUOROMETRY

We measured the time-dependent fluorescence intensity decays of anthracene and 9,10-dimethylanthracene in propylene glycol quenched by N,N-diethylaniline by frequency-domain fluorometry. The frequency-domain data, for a range of temperatures and diffusion coefficients, are consistent with a rate of quenching which depends exponentially on the fluorophore-quencher separation distance. This type of quenching interaction explains upward curvature in the Stern-Volmer plots. In total, the steady-state and time-resolved data are consistent with a mechanism of quenching due to the electron transfer process from DEA to the singlet excited anthracene molecules.