Research summary: Real time observation of chemical reactions by femtosecond time-resolved spectroscopy. Present specialized field: Physical chemistry (Keyword:Ultrafast spectroscopy, time-resolved spectroscopy, energy transfer, electron transfer, solvation, reaction dynamics, nuclear wavepacket dynamics) Yutaka Nagasawa has developed the techniques of ultrafast time-resolved spectroscopy, and have conducted a study based on real time measurement of photochemical reaction dynamics in the condensed matters.