Femtosecond CARS of methanol-water mixtures

We utilize femtosecond time-resolved coherent anti-Stokes Raman spectroscopy (CARS) to study the vibrational dynamics of methanol-water solutions. We measure the beat wavenumbers between Raman modes and coherence decay rates of C-H stretch modes (at 2835 cm(-1) and 2943 cm(-1)) in methanol. We observe a qualitative dependence of the coherence relaxation rate on the concentration of methanol in its water solution. This may be linked to the formation of the recently observed supramolecular structures in methanol-water mixtures. Copyright (C) 2006 John Wiley & Sons, Ltd.