Subpicosecond fluorescence dynamics of dye molecules

Time- and frequency-resolved fluorescence of dye molecules with femtosecond resolution gives new information on the intramolecular and intermolecular dynamics of large molecules in solution. We analyze data that were obtained recently by the upconversion technique together with new results: Access to vibrational coherence effects and to vibrational redistribution, thermalization, and cooling is illustrated for fluorescent dyes. The ultrafast fluorescence decay that accompanys internal conversion of a triphenylmethane dye is also analyzed.