Research Papers in Physics and Astronomy


Date of this Version



Published in Science 374, 178–182 (2021) 8 October 2021

DOI: 10.1126/science.abk3132

Cite as: arXiv:2107.03592 [physics.chem-ph] (or arXiv:2107.03592v1 [physics.chem-ph] for this version)


Copyright © 2021 by the authors


Conformational isomers (conformers) of molecules play a decisive role in biology and organic chemistry. However, experimental methods for investigating chemical reaction dynamics are typically not conformersensitive. We report on a gas-phase megaelectronvolt ultrafast electron diffraction investigation of a-phellandrene undergoing an electrocyclic ring-opening reaction. We directly imaged the evolution of a specific set of a-phellandrene conformers into the product isomer predicted by the Woodward-Hoffmann rules in real space and time. Our experimental results are in quantitative agreement with nonadiabatic quantum molecular dynamics simulations, which provide considerable detail of how conformation influences the time scale and quantum efficiency of photoinduced ring-opening reactions.

Supplemental files attached.