FEMTOSECOND OPTICAL KERR-EFFECT STUDIES OF WATER

The time-resolved optical Kerr effect of water at 298 K was investigated using pulse widths (full width at half-maximum) as short as 38 fs to characterize the dynamic response of water from tens of femtoseconds to several picosecond time scales. A frequency analysis of the free induction decay of the excited Raman modes observed maxima at 40 and 165 cm(-1), with a broad distribution of higher frequency components centered around 470 cm(-1). There is an initial rapid decay in the induced birefringence of less than 50 fs due to interference between these modes. These features are id good agreement with previous depolarized light scattering studies. Additional relaxation components of 500 +/- 30 fs and 1.7 +/- 0.3 ps are resolved in the Kerr results. In total, these observations depict an overall dynamic pathway for the relaxation of water.