Femtosecond studies of electron photodetachment of simple ions in liquid water: Solvation and geminate recombination dynamics

Femtosecond studies of electron photodetachment in aqueous solutions of NaCl and NaOH have been performed. The decays observed in the solvated electron absorption signal we believe to be the first direct observation of geminate electron–atom recombination. The solvation dynamics of the electron originating from a Cl− ion are slower, 500 fs, than the electron originating from a neutral water molecule, 350 fs. The recombination and solvation dynamics strongly suggest that short-range molecular effects are important.