The excess energy dissipation process of photoexcited S 1 trans-stilbene in solution has been studied with picosecond time-resolved Raman spectroscopy. The peak position of the 1570-cm -1 band (CdC stretch) is shown to be useful as an indicator of picosecond temperature changes; a picosecond time-resolved Raman spectrometer can be regarded as a "picosecond Raman thermometer". The cooling rates of S 1 trans-stilbene thus observed in 10 different solvents show a strong correlation with the thermal diffusivities of the bulk solvents. Based on this observation, a simple numerical model is proposed for the solute-solvent energy dissipation process in solution. The observed cooling kinetics are analyzed with this macroscopic model. It is concluded that the excess energy is first shared among the solute and the nearest solvent molecules in a few picoseconds or faster. The further heat conduction to outer-sphere solvent molecules determines the whole dissipation rate, which explains the observed correlation between the vibrational cooling rate and the thermal diffusivity of the solvent.

We show several pieces of Raman spectroscopic evidence that are indicative of local structure formation in imidazolium-based ionic liquids. Low-frequency Raman spectra of C n mimX, where C n mim stands for 1-alkyl(C n H 2 n+1 )-3-methylimidazolium cation and X represents the anion, exhibit broad bands assignable to collective modes of local structures. Spatial distributions of coherent anti-Stokes Raman scattering (CARS) signals from C n mim[PF 6] are consistent with local structures whose size increases with increasing n. Picosecond Raman spectra of S 1 trans-stilbene as a "picosecond Raman thermometer" show microscopic thermal inhomogeneity ascribable to local structure formation in C 2mimTf 2N and C 4mimTf 2N. We also describe two novel phenomena that we believe are relevant to extraordinary nanoenvironments generated by local structures in a magnetic ionic liquid C 4mim[FeCl 4].

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SEMSs were associated with a longer patency than PSs in patients with unresectable hilar biliary stricture. SEMSs were also more advantageous in reducing the number of reintervention sessions and the overall treatment cost.