Vibrational Dephasing of Simple Liquids Investigated by Picosecond and Femtosecond CARS

Abstract Using picosecond CARS the dephasing rate of the ν1‐mode of CS2 is investigated in several solvents and in the neat liquid. A large pressure effect (factor of ≤3) is reported for the range 0 to 4 kbar similar to spontaneous Raman results. For an extended interval of 160 to 450 K, a non‐monotonic temperature dependence is reported for the first time and compared with theoretical models. — A novel non‐degenerate CARS spectrometer is described with 80 fs time resolution and improved measuring accuracy. A dephasing time of T2 = 608 ± 6 fs is reported for the ν1 mode of neat acetone of 293 K; negligible inhomogeneous broadening (< 1%) is indicated by the scattering data for this vibration.