Time-resolved photo-induced dynamics of cis,cis-1,3-cyclooctadiene (COD) studied by Ultrafast Electron Diffraction

ORAL

Abstract

We investigated real-time photo-induced structural dynamics of a large-flexible cyclic conjugated diene molecule cis,cis-1,3-cyclooctadiene (COD), with an aim to extend the current knowledge beyond small rigid systems, such as 1,3-cyclohexadiene (CHD). We excited COD in the gas-phase with a 200 nm laser and performed measurements with the ultrafast electron diffraction set-up in the SLAC MeV-UED facility. We followed the photo-induced structural dynamics and determined photo products by a fitting-based analysis with the aid of trajectory surface hopping calculations. We found hot ground-state of COD and the electrocyclic ring closure product bicyclo[4.2.0]oct-7-ene (BCO) to be the main products. Our results indicate that most of the population reaches the ground state within a time of 200 fs and that the BCO is formed soon after the wavepacket reaches the ground state. Through comparison of the measured and calculated observables, we identified a periodic breathing motion from the hot ground-state of COD. The combination of a structurally sensitive experiment and high-level theory highlights the photochemistry and unique structural dynamics in the larger cyclic conjugated molecular system.

*This work was supported by the Department of Energy, Office of Science, Basic Energy Sciences, under award number DE-SC0020276

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Presenters

  • Sri Bhavya Muvva

    • Department of Physics and Astronomy, University of Nebraska–Lincoln, Lincoln, NE, USA

Authors

  • Sri Bhavya Muvva

    • Department of Physics and Astronomy, University of Nebraska–Lincoln, Lincoln, NE, USA

  • Yusong Liu

    • LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA, USA

  • Pratip Chakraborty

    • Department of Chemistry, KTH Royal Institute of Technology, Stockholm, Sweden

  • Pedro Nunes

    • Department of Physics and Astronomy, University of Nebraska–Lincoln, Lincoln, NE, USA

  • Spiridoula Matsika

    • Department of Chemistry, Temple University, Philadelphia, Pennsylvania, USA

  • Thomas Weinacht

    • Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York, USA
    • Stony Brook University

  • Martin Centurion

    • University of Nebraska - Lincoln
    • Department of Physics and Astronomy, University of Nebraska–Lincoln, Lincoln, NE, USA