title: Relaxation Processes in Aqueous Systems upon X-ray Ionization: Entanglement of Electronic and Nuclear Dynamics.
abstract: The knowledge of primary processes following the interaction of high-energy radiation with molecules in liquid phase is rather limited. In the present Perspective, we report on a newly discovered type of relaxation process involving simultaneous autoionization and proton transfer between adjacent molecules, so-called proton transfer mediated charge separation (PTM-CS) process. Within PTM-CS, transients with a half-transferred proton are formed within a few femtoseconds after the core-level ionization event. Subsequent nonradiative decay of the highly nonequilibrium transients leads to a series of reactive species, which have not been considered in any high-energy radiation process in water. Nonlocal electronic decay processes are surprisingly accelerated upon proton dynamics. Such strong coupling of electronic and nuclear dynamics is a general phenomenon for hydrogen-bonded systems, however, its probability correlates strongly with hydration geometry. We suggest that the newly observed processes will impact future high-energy radiation-chemistry-relevant modeling, and we envision application of autoionization spectroscopy for identification of solution structure details.
authors.affiliation: Department of Physical Chemistry, University of Chemistry and Technology , Technická 5, 16628 Prague, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Slavíček
authors.affiliation: Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg , Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany.
authors.forename: Nikolai V
authors.initials: NV
authors.lastname: Kryzhevoi
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie, Methods for Material Development , Albert-Einstein-Straße 15, D-12489 Berlin, Germany.|Department of Physics, Freie Universität Berlin , Arnimallee 14, D-14159 Berlin, Germany.
authors.forename: Emad F
authors.initials: EF
authors.lastname: Aziz
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie, Methods for Material Development , Albert-Einstein-Straße 15, D-12489 Berlin, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Winter