Communications Physics (Oct 2023)

X-ray induced Coulomb explosion imaging of transient excited-state structural rearrangements in CS2

  • James Unwin,
  • Felix Allum,
  • Mathew Britton,
  • Ian Gabalski,
  • Hubertus Bromberger,
  • Mark Brouard,
  • Philip H. Bucksbaum,
  • Taran Driver,
  • Nagitha Ekanayake,
  • Diksha Garg,
  • Eva Gougoula,
  • David Heathcote,
  • Andrew J. Howard,
  • Paul Hockett,
  • David M. P. Holland,
  • Sonu Kumar,
  • Chow-shing Lam,
  • Jason W. L. Lee,
  • Joseph McManus,
  • Jochen Mikosch,
  • Dennis Milesevic,
  • Russell S. Minns,
  • Christina C. Papadopoulou,
  • Christopher Passow,
  • Weronika O. Razmus,
  • Anja Röder,
  • Arnaud Rouzée,
  • Michael Schuurman,
  • Alcides Simao,
  • Albert Stolow,
  • Atia Tul-Noor,
  • Claire Vallance,
  • Tiffany Walmsley,
  • Daniel Rolles,
  • Benjamin Erk,
  • Michael Burt,
  • Ruaridh Forbes

DOI
https://doi.org/10.1038/s42005-023-01414-7
Journal volume & issue
Vol. 6, no. 1
pp. 1 – 11

Abstract

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Abstract Structural imaging of transient excited-state species is a key goal of molecular physics, promising to unveil rich information about the dynamics underpinning photochemical transformations. However, separating the electronic and nuclear contributions to the spectroscopic observables is challenging, and typically requires the application of high-level theory. Here, we employ site-selective ionisation via ultrashort soft X-ray pulses and time-resolved Coulomb explosion imaging to interrogate structural dynamics of the ultraviolet photochemistry of carbon disulfide. This prototypical system exhibits the complex motifs of polyatomic photochemistry, including strong non-adiabatic couplings, vibrational mode couplings, and intersystem crossing. Immediately following photoexcitation, we observe Coulomb explosion signatures of highly bent and stretched excited-state geometries involved in the photodissociation. Aided by a model to interpret such changes, we build a comprehensive picture of the photoinduced nuclear dynamics that follows initial bending and stretching motions, as the reaction proceeds towards photodissociation.