Competing proton-transfer and electron-transfer dynamics, probed by coulomb explosion imaging Daniel Strasser The Hebrew University of Jerusalem, Israel In the well-known harpoon reaction, long-range electron-transfer results in Coulombic attraction between initially neutral reactants that leads to dramatic increase in the reaction rate. Here I will present a different “inverse harpoon” mechanism in which electron-transfer from a neutral reactant to a multiply charged cation results in strong repulsion that encodes the electron-transfer distance in the kinetic energy release. 3D coincidence imaging experiments allowed identifying and characterizing the electron-transfer events that are predicted by non-adiabatic molecular dynamics simulations to occur following double-ionization of isolated methanol molecules between a roaming neutral H 2 and HCOH 2+ . The roaming H 2 dynamics are initiated by single-photon double ionization of isolated methanol molecules by an ultrafast EUV pulse produced by HHG. Theensuingdynamics of the long-range electron-transfer mechanism competes with proton-transfer that forms H 3 + + COH + products on an ultrafast ~100fs time scale, as determined by ultrafast EUV pump – near IR probe experiments. Detailed comparison of the experimental and theoretically simulated product branching ratios and kinetic energy distributions provides intimate information about the competing charge-transfer mechanisms and in particular about the distance at which electron-transfer occurs. References 1. E. Livshits, I. Luzon, K. Gope, R. Baer & D. Strasser, ”Time-resolving the ultrafast H 2 roaming chemistry and H 3 + formation using extreme-ultraviolet pulses.” Commun. Chem. 3, 49 (2020). https://www.nature.com/articles/s42004-020-0294-1 2. K. Gope, E. Livshits, D.M. Bittner, R. Baer & D. Strasser, An “Inverse” Harpoon Mechanism. Sci. Adv. 8, eabq8084 (2022). https://www.science.org/doi/10.1126/sciadv.abq8084
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