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Published January 19, 2001 | public
Journal Article

Direct Imaging of Transient Molecular Structures with Ultrafast Diffraction


Ultrafast electron diffraction (UED) has been developed to study transient structures in complex chemical reactions initiated with femtosecond laser pulses. This direct imaging of reactions was achieved using our third-generation apparatus equipped with an electron pulse (1.07 ± 0.27 picoseconds) source, a charge-coupled device camera, and a mass spectrometer. Two prototypical gas-phase reactions were studied: the nonconcerted elimination reaction of a haloethane, wherein the structure of the intermediate was determined, and the ring opening of a cyclic hydrocarbon containing no heavy atoms. These results demonstrate the vastly improved sensitivity, resolution, and versatility of UED for studying ultrafast structural dynamics in complex molecular systems.

Additional Information

© 2001 American Association for the Advancement of Science. Received 26 September 2000; accepted 28 November 2000. Supported by NSF and the U.S. Air Force Office of Scientific Research. We thank H. E. Elsayed-Ali for collaboration on the construction of the electron gun.

Additional details

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October 18, 2023