Excited state isomerization of a cyanine dye investigated with femtosecond fluorescence up-conversion technique

Excited state isomerization reaction of cyanine dye has been considered as a typical barrierless reaction. The experimental research based on the dye´s excited state dynamics has been performed by using several different time-resolved techniques, including excited state absorption, stimulated emission and fluorescence. In this report, employing femtosecond laser pulses, we studied the ultrafast time-resolved dynamics of fluorescence in solutions of cyanine dye 3,3´-di(3-sulfopropyl)thiacyanine triethylaimonium salt in water with and without doping semiconductor TiO/sub 2/ colloids.