NONEXPONENTIAL DEPHASING OF MOLECULAR VIBRATIONS IN LIQUIDS, DIRECTLYOBSERVED BY MAGIC FEMTOSECOND CARS

Using 'magic' polarization geometries in time-resolved coherent anti-S tokes Raman spectroscopy, the isotropic (purely vibrational) scatterin g contribution was investigated. Non-exponential dephasing was observe d on the subpicosecond time-scale, described in the Anderson-Kubo form alism by the correlation time tau(c). Experimental data are reported f or the neat liquids CH2BrCl and (CH3)(2)SO in the CH stretching region . Values of tau(c) = 330 fs and 240 fs, respectively indicate, homogen eous line broadening for the dephasing processes. The time-domain data are supported by a novel analysis of spontaneous Raman data.