Vibrational Cooling Process of S_1 trans-Stilbene in Ionic Liquids Observed with Picosecond Time-resolved Raman Spectroscopy
Vibrational cooling rates in room temperature ionic liquids were measured with picosecond time-resolved Raman spectroscopy. The 1570-cm<SUP>−1</SUP> Raman band of the first excited singlet (S<SUB>1</SUB>) state of <I>trans</I>-stilbene was used as a "Raman thermometer." The recorded vibrational cooling rates in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (emimTf<SUB>2</SUB>N) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (bmimTf<SUB>2</SUB>N) were close to those in ordinary molecular solvents despite a large difference in thermal diffusivity. The result is consistent with the assumption that local structures are formed in the ionic liquids.
- Chemistry letters
Chemistry letters 36(4), 504-505, 2007-04-05
The Chemical Society of Japan