Femtosecond CARS on molecules exhibiting ring puckering vibration in gas and liquid phase

We present a comparison of results obtained by Raman and fs coherent anti-Stokes Raman scattering (CARS) spectroscopy on four molecules with puckered rings, analyzing the ring puckering band progressions. The dynamics are probed in gas and liquid phase. For the gas phase a rich beating structure is observed in the anti-Stokes signal over many picoseconds while the liquid phase transients rapidly decay. Therefore, fast Fourier analysis yields highly resolved lines for the molecules in gas phase, which can be assigned to the Raman modes. No effect due to rotational orientation changes could be observed.