ELECTRONIC EXCITATION TRANSFER FROM PYRENE TO PERYLENE BY A VERY WEAK INTERACTION MECHANISM

The singlet-singlet electronic excitation transfer from pyrene to perylene in high polymer matrices has been investigated by measuring the fluorescence decay curve of pyrene using the nanosecond-flash light for excitation. The results of measurements in polymethyl methacrylate and polystyrene clearly showed that the excitation transfer occurred by the dipole-dipole coupling of the very weak interaction mechanism, and Förster's formula for the fluorescence decay curve in the case of fixed donors and acceptors was accurately satisfied. Although polystyrene has low-lying π-electronic energy levels compared to polymethyl methacrylate, the possibility of the indirect coupling through the π-electronic states of polystyrene was excluded.