Hannover 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MO: Fachverband Molekülphysik
MO 2: Collisions, Energy Transfer
MO 2.6: Vortrag
Montag, 8. März 2010, 15:15–15:30, F 142
Fragmentation of protonated water by low-energy electrons — •Julia Stützel1, Henrik Buhr2,1, Oldřich Novotný3,1, Max H. Berg1, Dennis Bing1, Manfred Grieser1, Brandon Jordon-Thaden1, Jens Hoffmann1, Claude Krantz1, Mario Mendes1, Steffen Novotny1, Dimitry A. Orlov1, Annemieke Petrignani1, Andrey Shornikov1, and Andreas Wolf1 — 1Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany — 2Department of Particle Physics, Weizmann Institute of Science, 76100 Rehovot, Israel — 3Columbia Astrophysics Laboratory, 550 West 120th Street, MC 5247, New York, NY 10027, USA
Dissociative Recombination (DR) of H3O+ with cold (few meV) electrons is believed to be the major source of water production in interstellar clouds. Momentum spectroscopy of collision products from a stored D3O+ ion beam merged with an intense cold electron beam showed a branching ratio of ∼17% for D2O production, with at least half of these products internally excited by more than 4 eV. In addition, recent analysis of the Dalitz Plot of the dominant (∼ 71%) three-body dissociation channel D + D + OD indicates the intermediate formation of unstable water molecules above their dissociation barrier. The decay of the molecules on their way to the coincidence detector yields characteristic structures in the Dalitz geometry map. The significant internal excitation we found in the stored D3O+ might be of importance for the occurrence of the observed two-step dissociation.