Diffractive imaging of a molecular rotational wavepacket with femtosecond Megaelectronvolt electron pulses

Jie Yang; Markus Guehr; Theodore Vecchione; Matthew S. Robinson; Renkai Li; Nick Hartmann; Xiaozhe Shen; Ryan Coffee; Jeff Corbett; Alan Fry; Kelly Gaffney; Tais Gorkhover; Carsten Hast; Keith Jobe; Igor Makasyuk; Alexander Reid; Joseph Robinson; Sharon Vetter; Fenglin Wang; Stephen Weathersby; Charles Yoneda; Martin Centurion; Xijie Wang

doi:10.1038/ncomms11232

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arXiv · 1510.06426

Diffractive imaging of a molecular rotational wavepacket with femtosecond Megaelectronvolt electron pulses

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Abstract

Imaging changes in molecular geometries on their natural femtosecond timescale with sub-Angstrom spatial precision is one of the critical challenges in the chemical sciences, since the nuclear geometry changes determine the molecular reactivity. For photoexcited molecules, the nuclear dynamics determine the photoenergy conversion path and efficiency. We performed a gas-phase electron diffraction experiment using Megaelectronvolt (MeV) electrons, where we captured the rotational wavepacket dynamics of nonadiabatically laser-aligned nitrogen molecules. We achieved an unprecedented combination of 100 fs root-mean-squared (RMS) temporal resolution and sub-Angstrom (0.76 Å) spatial resolution that makes it possible to resolve the position of the nuclei within the molecule. In addition, the diffraction patterns reveal the angular distribution of the molecules, which changes from prolate (aligned) to oblate (anti-aligned) in 300 fs. Our results demonstrate a significant and promising step towards making atomically resolved movies of molecular reactions.

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Jie Yang, Markus Guehr, Theodore Vecchione, Matthew S. Robinson, Renkai Li, Nick Hartmann, Xiaozhe Shen, Ryan Coffee, Jeff Corbett, Alan Fry, Kelly Gaffney, Tais Gorkhover, Carsten Hast, Keith Jobe, Igor Makasyuk, Alexander Reid, Joseph Robinson, Sharon Vetter, Fenglin Wang, Stephen Weathersby, Charles Yoneda, Martin Centurion, Xijie Wang. 2015-10-21. Diffractive imaging of a molecular rotational wavepacket with femtosecond Megaelectronvolt electron pulses. https://doi.org/10.1038/ncomms11232

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