FAST RESPONSES FROM SLOWLY RELAXING LIQUIDS - A COMPARATIVE-STUDY OF THE FEMTOSECOND DYNAMICS OF TRIACETIN, ETHYLENE-GLYCOL, AND WATER

We have measured the ultrafast solvent relaxation of liquid ethylene g lycol, triacetin, and water by means of femtosecond polarization spect roscopy, using optical-heterodyne-detected Raman-induced Kerr-effect s pectroscopy. In the viscous liquids triacetin and ethylene glycol, fem tosecond relaxation processes were resolved. Not surprisingly, the fem tosecond nonlinear optical response of ethylene glycol is quite simila r to that of water. Using the theory of Maroncelli, Kumar, and Papazya n, we transform the pure-nuclear solvent response into a dipolar-solva tion correlation function for comparison with ultrafast electron-trans fer reaction rates.