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MO: Fachverband Molekülphysik
MO 13: Ultrafast Dynamics II
MO 13.6: Vortrag
Mittwoch, 12. März 2025, 12:15–12:30, HS XVI
Unraveling the dynamics of ionized water dimer in a highly-purified molecular beam — •Ivo S. Vinklárek1, Hubertus Bromberger1, Luisa Blum1,2, Sebastian Trippel1, and Jochen Küpper1,2,3 — 1Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany — 2Department of Physics, Universität Hamburg, Hamburg, DE — 3Center for Ultrafast Imaging, Universität Hamburg, Hamburg, DE
Radiation chemistry in biochemical systems is primarily driven by the ultrafast dynamics of water molecules after absorption of ionizing radiation. The initial water response to the ionization involves ultrafast hydrogen-bond-mediated proton transfer (PT), which was recently probed in the prototypical water-dimer cation (H2O)2 [1], and subsequent fragmentation into highly reactant ions and radicals.
Our detailed study utilizing purified molecular beams of (H2O)2 [2] revealed that (H2O)2+ can either stabilize or undergo fragmentation along more than ten distinct pathways. While theoretical studies have explored the rates and dynamics of some of these reactions, experimental evidence is completely lacking. To address this, we employed a disruptive-probing scheme [3] that allows us to track early PT dynamics and the populations of ionic products, thus directly yielding effective reaction-rate constants. These findings provide crucial insights into ionizing processes in both the atmosphere and living organisms.
[1] Schnorr, K. et al., Sci. Adv. 9, eadg7864 (2023)
[2] Vinklárek, I.S. et al., J. Phys. Chem. A 128, 1593 (2024),
[3] Jochim, B. et al., Rev. Sci. Instrum. 93, 033003 (2022)
Keywords: supramolecular chemistry; hydrogen bonding; disruptive probing; radiation chemistry