Generation of solvated electrons in neat water: new results from femtosecond spectroscopy

Femtosecond spectroscopy in an extended spectral range of up to 5.5 mum is demonstrated of a water (D2O) sample after two photon excitation at 9.1 eV. The data provides clear evidence for two short-lived precursors of the hyd rated electron previously not identified. The first novel precursor determi ned here with peak absorption at 2.9 (4.1) mum is proposed to represent an OH(D):e(-) complex. The subsequent solvation proceeds via e(-):((H,D)(2)O)( n) complexes at approximately 1.6 (2.0) mum in the electronic ground state. An increasing number of water molecules are involved in the built up of th e trap around the photogenerated electron during the first 200 fs. (C) 2001 Elsevier Science B.V. All rights reserved.