Hydrogen Atom Transfer from Water or Alcohols Activated by Presolvated Electrons.
High-energy irradiation of protic solvents can transiently introduce excess electrons that are implicated in a diverse range of reductive processes. Here we report the evolution of electron solvation in water and in alcohols following photodetachment from aqueous hydroxide or the corresponding alkoxides studied by two- and three-pulse femtosecond spectroscopy and ab initio molecular dynamic simulations. The experiments reveal an ultrafast recombination channel of the excess electrons. Through the calculations this channel emerges as an H-atom transfer process to the hydroxyl or alkoxy radical species from neighboring solvent molecules, which are activated as the presolvated electron occupies their antibonding orbitals. The initially low activation barrier in the early stages of electron solvation was found to increase (from 12 to 44 kJ/mol in water) as full solvation proceeded.
†Physik-Department, Technische Universität München, James-Franck-Strasse, D-85748 Garching, Germany.
Hristo
H
Iglev
‡Faculty of Chemistry and Pharmacy, University of Sofia, Blvd. J. Bauchier 1, 1126 Sofia, Bulgaria.
Stefan K
SK
Kolev
†Physik-Department, Technische Universität München, James-Franck-Strasse, D-85748 Garching, Germany.
Hubert
H
Rossmadl
‡Faculty of Chemistry and Pharmacy, University of Sofia, Blvd. J. Bauchier 1, 1126 Sofia, Bulgaria.|∥Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany.
Petko
P
St Petkov
‡Faculty of Chemistry and Pharmacy, University of Sofia, Blvd. J. Bauchier 1, 1126 Sofia, Bulgaria.
Georgi N
GN
Vayssilov
CTTS; antibonding states; photodetachment; pump−repump−probe spectroscopy; quantum simulations; solvated electron