REMARKS ON FLUORESCENCE CONCENTRATION QUENCHING OF RHODAMINE 6G IN METHANOL

It has been shown that the concentration changes in the quantum yield eta and decay time tau of fluorescence of rhodamine 6G in methanol can be explained quantitatively by non-radiative excitation energy transport (NET) from monomers to quenching centres considered as perfect traps. The good agreement of the experimental data with the theoretical curves for the critical radii R(OMM) = 55.4 angstrom and R(OMT) = 51.8 angstrom determined spectroscopically has been obtained. The excitation energy migration and the concentration dependence on the orientation factor occurring in the Forster rate for the NET have been taken into account. The nature of the quenching centres and the effect of material diffusion of active molecules on eta and tau have been discussed.