田原分子分光研究室 Molecular Spectroscopy Laboratory



Observation and Control of the Excited State Dynamics of Condensed Phase Molecules by Advanced Spectroscopy Using Ultrashort Optical Pulses

Hikaru Kuramochi

Tracking the molecular dynamics from the electronic and structural viewpoints is essential for deep understanding of chemical reactions. To this end, we develop new ultrafast spectroscopic methods based on basic knowledge on the light-matter interaction and state-of-the-art laser technology. Using these advanced spectroscopy, we aim to observe, understand, and control new fundamental phenomena of reactive molecules.

Research outline

Elucidating the dynamics of chemical reactions is essential to achieving a deep understanding of the processes involved. With this idea in mind, we study the dynamics of photoexcited molecules via a variety of time-resolved spectroscopic methods utilizing ultrashort laser pulses. We develop new spectroscopic methods based on state-of-the-art laser technology and aim to observe, understand, and control new fundamental phenomena of reactive molecules. Especially for ultrafast reactions, it is key to observe and “visualize” the continuous motion of nuclei (structural change) throughout the reaction. Therefore, we study the “instantaneous” structures of the reacting molecules by advanced multi-pulse experiments, and try to determine the structure of the transition state that plays crucial roles in chemical reactions.


Ultrashort pulse generation and multi-color time-resolved spectrometers

Observation of coherent nuclear motion in ultrafast photochemical reactions

Structural tracking of reacting molecules by femtosecond time-domain Raman spectroscopy

Ultrafast excited state dynamics of metal complexes


Hikaru Kuramochi (group leader)

Pardeep Kumar

Tsukasa Takanashi

Li Liu

Chun-Fu Chang

Selected publications

  1. H. Kuramochi; S. Takeuchi; K. Yonezawa; H. Kamikubo; M. Kataoka; T. Tahara
    Probing the early stages of photoreception in photoactive yellow protein with ultrafast time-domain Raman spectroscopy
    Nat. Chem., 9, 7, 660 – 666 (2017).
  2. H. Kuramochi; S. Takeuchi; T. Tahara
    Femtosecond time-resolved impulsive stimulated Raman spectroscopy using sub-7-fs pulses: Apparatus and applications
    Rev. Sci. Instrum., 87, 043107, 1 – 10, (2016).
  3. T. Fujisawa; H. Kuramochi; H. Hosoi; S. Takeuchi; T. Tahara
    Role of coherent low frequency motion in excited state proton transfer of green fluorescenct protein studied by time-resolved impulsive Raman spectroscopy
    J. Am. Chem. Soc., 138, 3942 – 3945 (2016).
  4. S. Tahara; S. Takeuchi; R. Abe-Yoshizumi; K. Inoue; H. Ohtani; H. Kandori; T. Tahara
    Ultrafast photoreaction dynamics of a light-driven sodium-ion-pumping retinal protein from Krokinobacter eikastus revealed by femtosecond time-resolved absorption spectroscopy
    J. Phys. Chem. Lett., 6, 4481 – 4486 (2015).
  5. M. Iwamura; K. Nozaki; S. Takeuchi; T. Tahara
    Real-time observation of tight Au-Au bond formation and relevant coherent motion upon photoexcitation of [Au(CN)2] oligomers
    J. Am. Chem. Soc., 135, 538 – 541 (2013).