Stuttgart 2012 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 21: Poster 3: Cluster, Collisions, Energy Transfer, Photochemistry, Spectroscopy in He-Droplets
MO 21.17: Poster
Donnerstag, 15. März 2012, 16:30–19:00, Poster.IV
Electron diffraction self imaging of molecular fragmentation in two step double ionization of water — •Hendrik Sann1, Till Jahnke1, Tilo Havermeier1, Katharina Kreidi1, Christian Stuck1, Moritz Meckel1, Markus Schöffler1, Nadine Neumann1, Robert Wallauer1, Stefan Voss1, Achim Czasch1, Ottmar Jagutzki1, Thorsten Weber2, Horst Schmidt-Böcking1, Shungo Miyabe2, Daniel J. Haxton2, Ann E. Orel3, Thomas N. Rescigno2, and Reinhard Dörner1 — 1Institut für Kernphysik, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany — 2Lawrence Berkeley National Laboratory, Chemical Sciences and Ultrafast X-ray Science Laboratory, Berkeley, California 94720, USA — 3Department of Applied Science, University of California, Davis, CA 95616, USA
We doubly ionize H2O by single photon absorption at 43 eV leading to H+ + OH+. A direct double ionization and a sequential process in which single ionization is followed by rapid dissociation into a proton and an autoionizing OH* is identified. The angular distribution of this delayed autoionization electron shows a preferred emission in the direction of the emitted proton. This anisotropy can be reproduced almost exactly with a simple classical scattering simulation. From this simulation we obtain an internuclear distance of 800 a.u. at which the autoionization occurs.
This scattering effect should be rather general and should occur whenever a positively charged fragment is emitted from a molecule or cluster and at a later time electrons are emitted.