Study of Ultrafast Kinetics

Interrogation of nuclear dynamics at the temporal resolution of nuclear motion 
Ultrafast Raman Loss Spectroscopy

Ultrafast stimulated Raman has provided a new way to acquire vibrational signature of the transient species in a photochemical transformation. Using ultrashort pulses (100 femtoseconds) one can create and monitor transient structural change through nonlinear stimulated Raman technique. We have developed a new method to acquire vibrational Raman signature free from fluorescence background. Combining three optical pulses namely Photo-pump (100 fs), broadband probe (100 fs) and Raman pump (1 ps) and with sophisticated data acquiring method we could observe Raman signature of the short-lived species. By applying multiple ultrashort pulses to a molecular system we are able to detect loss signal at the anti-Stoke’s side. This spectroscopic technique is known as ultrafast Raman loss spectroscopy (URLS). We are currently studying ultrafast photo-isomerization, proton transfer and solvation effect in the excited state.