Isomerization and dissociation dynamics of 1,2-dichloroethylene probed by time-resolved Coulomb explosion imaging

ORAL

Abstract

Coulomb explosion imaging (CEI) is a powerful method to obtain detailed structural information of small quantum systems, such as molecules and clusters, in the gaseous phase. Time-resolved CEI (TRCEI) initiated by ultrafast laser pulses provides a unique opportunity to follow structural and fragmentation dynamics with high temporal resolution. While studying photoinduced isomerization reactions, TRCEI can be used not only to distinguish different isomer geometries but also to track the time evolution during the interconversion between those geometries. Here, we present an application of TRCEI to the cis and trans isomers of 1,2-dichloroethylene (C2H2Cl2) (DCE). After excitation by a 200-nm UV pulse, a high-intensity near-infrared laser pulse is used to induce Coulomb explosion at different time delays between the two pulses. The fragments thus produced are detected in coincidence, and their correlated momenta are used to determine the evolving molecular structure. DCE can follow multiple pathways upon UV excitation, including direct C-Cl bond cleavage, fragment rotation, isomerization, molecular chlorine formation, etc. We discuss the contributions of these different pathways for both the isomers of DCE in the light of different experimental observables. Furthermore, we compare the experimental results with classical Coulomb explosion simulations to guide our interpretations. Our study sheds light on the photoinduced isomerization reaction at the molecular level.

*This work is supported by the Chemical Science, Geosciences, and Bioscience Division, Office of Basic Energy Science, Office of Science, U.S. Department of Energy, grants no. DE-FG02-86ER13491 and by the National Science Foundation grant no. PHYS-1753324 (AD, ASV). MB and JM acknowledge the support of the UK Engineering and Physical Sciences Research Council through Programme Grant EP/V026690/1.

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Presenters

  • Avijit Duley

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

Authors

  • Avijit Duley

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

  • Joseph McManus

    • Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, U.K.

  • FNU Shalauddin

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

  • Keyu Chen

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

  • Tu Thanh T Nguyen

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

  • Sanduni Kudagama

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

  • Surjendu Bhattacharyya

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

  • Anbu S Venkatachalam

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

  • Huynh Van Sa V Lam

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

  • Artem Rudenko

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

  • Mark Brouard

    • Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, U.K.

  • Daniel Rolles

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