FLUORESCENCE QUENCHING OF PERYLENE BY CO2+ IONS VIA ENERGY-TRANSFER IN VISCOUS AND NON-VISCOUS MEDIA

Non-radiative energy transfer from singlet excited perylene to Co2+ ions has been studied in methanol, ethylene glycol and glycerol by time-correlated single-photon counting and steady state quenching experiments. In highly viscous glycerol the decay curves are represented by the expression given by Forster for long-range energy transfer. The experimental critical distance R0 = 13.2 angstrom is in good agreement with the theoretical value. In methanol and ethylene glycol the decay is modified owing to translational motion and can be described by the function exp(- at - bt1/2) with reasonable values for the reaction sphere and diffusion coefficients.