FEMTOSECOND INTERMOLECULAR ELECTRON-TRANSFER IN DIFFUSIONLESS, WEAKLY POLAR SYSTEMS - NILE BLUE IN ANILINE AND N,N-DIMETHYLANILINE

Ultrafast, nonexponential fluorescence decays, ascribed to intermolecular electron transfer, are observed for nile blue in diffusionless, electron-donating solvent systems. In N,N-dimethylaniline, the decay is dominated by a lifetime as short as 100 fs. Electron transfer, limited only by ultrafast nuclear relaxation rather than by solvent dipolar reorientation, is thought to occur in weakly polar, highly polarizable aromatic systems of small solvent reorientation energy, where the nuclear reorientation energy is comparable to that of the solvent.