DIPHENYLOCTATETRAENE S2 EMISSION

Diphenyloctatetraene (DPO) fluorescence spectra were investigated by a time-resolved single-photon counting technique. Spectra of an ultrafast emission originating from the DPO S2 state were recorded in several solvents. The spectral shapes are approximately mirror images of the absorption spectra. The shift between the 0-0 band maxima of the absorption and S2 emission is small. The lifetime of the DPO S2 state can be estimated to be 70 fs from the emission radiative lifetime and quantum yield. The S2 emission anisotropy is close to the upper limit for a dipole transition, i.e. 0.4.