Lifetime quenching of the fluorophore: A signature of magnetic field maximization

The fluorescence lifetime quenching of the fluorophores in the presence of quenchers were measured with the variation of solvent polarity (epsilon) fo r the two donor-acceptor (D-A) pair, N-ethyl carbazole-l, 4 dicyanobenzene and pyrene-N,N-dimethylaniline. We observed that maximum quenching of lifet imes occurred at the epsilon where maximum magnetic held effects had been a chieved for both the pairs. The importance of the nature of the exciplex la d the distance between D and A in magnetic held maximization has also been elucidated.