Observation of the fastest chemical processes in the radiolysis of water
Zhi-Heng Loh, Gilles Doumy, Caroline Arnold, Ludvig Kjellsson, S. H. Southworth, André Al Haddad, Yoshiaki Kumagai, Ming-Feng Tu, Phay J. Ho, Anne Marie March, Richard D. Schaller, Muhammad Shafiq Bin Mohd Yusof, Tushar Debnath, M. Simon, Ralph Welsch, Ludger Inhester, Khadijeh Khalili, Kaushik Nanda, Anna I. Krylov, Stefan Moeller, Giacomo Coslovich, J. D. Koralek, Michael P. Minitti, W. F. Schlotter, Jan‐Erik Rubensson, Robin Santra, Linda Young
Abstract
The “hole” story of water ionization The direct observation of the cationic hole H 2 O + that is formed in liquid water after ionization has been a long-standing experimental challenge. Previous attempts using optical and ultraviolet techniques have failed to reveal its key spectroscopic signature during ultrafast transformation into a OH radical. Loh et al. address this gap by using intense, ultrafast x-ray pulses from an x-ray free electron laser at ∼530 electron volts. They found compelling evidence for the formation H 2 O + and its decay to an OH radical by a proton transfer mechanism and elucidated the other fastest–time scale steps in the early-time dynamics of ionized liquid water. Science , this issue p. 179