MeV Electron Diffractive Imaging of Competing Ring-Opening and Photodissociation

ORAL

Abstract

Here we present time-resolved MeV electron scattering results of 2-Iodothiophene and 3-Iodothiophene and interrogate the branching ratios between ring-opening and C-I bond cleavage following photoexcitation at 245 nm. After UV excitation, halothiophenes can either undergo ring-opening or prompt bond cleavage. The branching ratio between these processes is dependent on the wavelength, substitution position, and atom identity, as a result of the different substitution effects for the electron-withdrawing halogen. The use of ultrafast electron bunches to study time-resolved dynamics has become a powerful tool for probing transient geometries. Of particular interest is the ability to use this to quantitatively probe reactions that proceed along competing reaction coordinates. This time-resolved geometric comparison further elucidates the direct and indirect C-I cleavage processes identified in a recent coulomb explosion study of these same two isomers [1].

[1] W. Razmus et al. Exploring the Ultrafast and Isomer-Dependent Photodissociation of Iodothiophenes via Site-Selective Ionization (Submitted December 2023).

*A.M.G., M.B., F.A., B.K., K.L., J.G., and R.F. were supported by the Department of Energy Office of Basic Energy Science, Facilities Division. A.G., T.W., and P.H.B. were supported by the AMOS program within the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division. A.M.G. was additionally supported by an NSF Graduate Research Fellowship. The use of the MeV-UED instrument, which is operated as part of the Linac Coherent Light Source at the SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515.

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Presenters

  • Aaron M Ghrist

    • Stanford University

Authors

  • Aaron M Ghrist

    • Stanford University

  • Matthew Bain

    • SLAC National Accelerator Laboratory

  • Felix Allum

    • Stanford University

  • Brian M Kaufman

    • Stony Brook University

  • Yusong Liu

    • SLAC National Laboratory

  • Alice Green

    • Stanford PULSE Institute
    • SLAC National Accelerator Laboratory

  • Kirk Larsen

    • SLAC National Accelerator Laboratory

  • Surjendu Bhattacharyya

    • Kansas State University
    • SLAC National Accelerator Laboratory
    • J.R. Macdonald Laboratory, Kansas State University, Manhattan, KS, USA

  • John Searles

    • Kansas State University

  • Keyu Chen

    • Kansas State University

  • Michael P Minitti

    • SLAC National Accelerator Laboratory

  • Thomas J Wolf

    • SLAC National Accelerator Laboratory

  • James M Glownia

    • SLAC - Natl Accelerator Lab
    • SLAC National Accelerator Laboratory

  • Alexander H Reid

    • SLAC National Accelerator Laboratory

  • Christina Hampton

    • SLAC National Accelerator Laboratory

  • Daniel Rolles

    • J.R. Macdonald Laboratory, Kansas State University
    • Kansas State University
    • J.R. Macdonald Laboratory, Kansas State University, Manhattan, KS, USA

  • Thomas Weinacht

    • Stony Brook University

  • Andrew Orr-Ewing

    • University of Bristol

  • Dave Townsend

    • Heriot-Watt University

  • Michael Ashfold

    • University of Bristol

  • Philip H Bucksbaum

    • Stanford Univ
    • Stanford University

  • Russell S Minns

    • University of Southampton

  • Ruaridh Forbes

    • SLAC National Accelerator Laboratory