title: Ultrafast electron diffraction imaging of bond breaking in di-ionized acetylene.
abstract: Visualizing chemical reactions as they occur requires atomic spatial and femtosecond temporal resolution. Here, we report imaging of the molecular structure of acetylene (C2H2) 9 femtoseconds after ionization. Using mid-infrared laser-induced electron diffraction (LIED), we obtained snapshots as a proton departs the [C2H2]2+ion. By introducing an additional laser field, we also demonstrate control over the ultrafast dissociation process and resolve different bond dynamics for molecules oriented parallel versus perpendicular to the LIED field. These measurements are in excellent agreement with a quantum chemical description of field-dressed molecular dynamics.
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Wolter
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
authors.forename: M G
authors.initials: MG
authors.lastname: Pullen
authors.affiliation: J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS 66506-2604, USA.
authors.forename: A-T
authors.initials: AT
authors.lastname: Le
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Baudisch
authors.affiliation: Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Post Office Box 9502, 2300 RA Leiden, Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Doblhoff-Dier
authors.affiliation: Universität Kassel, Institut für Physik und CINSaT, Heinrich-Plett-Str. 40, 34132 Kassel, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Senftleben
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.|Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Centre for Ultrafast Imaging (CUI), 22607 Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hemmer
authors.affiliation: Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
authors.forename: C D
authors.initials: CD
authors.lastname: Schröter
authors.affiliation: Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.|Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Ullrich
authors.affiliation: Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Pfeifer
authors.affiliation: Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Moshammer
authors.affiliation: Institute for Physical Chemistry, Friedrich-Schiller University Jena, 07743 Jena, Germany.|Abbe Center of Photonics, Friedrich-Schiller-University Jena, 07743 Jena, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Gräfe
authors.affiliation: Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Centre for Ultrafast Imaging (CUI), 22607 Hamburg, Germany.|Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark.
authors.forename: O
authors.initials: O
authors.lastname: Vendrell
authors.affiliation: J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS 66506-2604, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Lin
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain. jens.biegert@icfo.eu.|Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Biegert