Novel resonance Raman enhancement of local structure around solvated electrons in water

Picosecond time-resolved Raman spectra of water were measured under the res onance condition with the s --> p electronic transition of the solvated ele ctron for the first time. We found that a strong transient Raman band appea rs in the frequency region 30 cm(-1) lower than the OH-bend band of bulk wa ter in accordance with the formation of solvated electrons. The observed tr ansient Raman band was assigned to the vibration of the solvating water mol ecules that strongly interact with the solvated electron in the first solva tion shell. The mechanism of this novel resonance enhancement is discussed on the basis of the vibronic theory.