Loh, Doumy, Arnold, Kjellsson, Southworth, Al Haddad, Kumagai, Tu, Ho, March, Schaller, Bin Mohd Yusof, Debnath, Simon, Welsch, Inhester, Khalili, Nanda, Krylov, Moeller, Coslovich, Koralek, Minitti, Schlotter, Rubensson, Santra, Young (2020) Observation of the fastest chemical processes in the radiolysis of water Science (New York, N.Y.) 367(6474) 179-182


Elementary processes associated with ionization of liquid water provide a framework for understanding radiation-matter interactions in chemistry and biology. Although numerous studies have been conducted on the dynamics of the hydrated electron, its partner arising from ionization of liquid water, H2O+, remains elusive. We used tunable femtosecond soft x-ray pulses from an x-ray free electron laser to reveal the dynamics of the valence hole created by strong-field ionization and to track the primary proton transfer reaction giving rise to the formation of OH. The isolated resonance associated with the valence hole (H2O+/OH) enabled straightforward detection. Molecular dynamics simulations revealed that the x-ray spectra are sensitive to structural dynamics at the ionization site. We found signatures of hydrated-electron dynamics in the x-ray spectrum. Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.