Probing Local Structure of Ionic Liquids with Picosecond Time-resolved Raman Spectroscopy

Vibrational cooling kinetics of the first excited singlet (S
₁
) state of
trans
-stilbene in ionic liquids was measured with picosecond time-resolved Raman spectroscopy. There was no correlation observed between the cooling rate and the thermal diffusivity of the solvent, suggesting the presence of local structures in the ionic liquids.