FEMTOSECOND STUDIES OF HYDRATED ELECTRON RECOMBINATION FOLLOWING MULTIPHOTON IONIZATION AT 390-NM

We report a femtosecond laser study of the power and wavelength dependence of the dynamics of the solvated electron produced through multiphoton ionization of water at 390 nm. While the localization dynamics are found to be in good agreement with previous studies exciting at 310 nm, nearly complete lack of geminate recombination is discovered on the time scale of up to 700 ps, in marked contrast to the substantial geminate recombination observed with 310 or 248 nm excitation. The results suggest that the electron-cation geminate recombination process is sensitive to the excitation wavelength both mechanistically and energetically.