Düsseldorf 2007 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 29: Poster: Cold Molecules
MO 29.4: Poster
Dienstag, 20. März 2007, 16:30–18:30, Poster A
Interactions of negative ions in multipole traps — •Jochen Mikosch1, Sebastian Trippel1, Rico Otto1, Markus Debatin1, Michael Kröner2, Christoph Eichhorn1, Peter Woias2, Matthias Weidemüller1, and Roland Wester1 — 1Physikalisches Institut, Universität Freiburg — 2Institut für Mikrosystemtechnik, Universität Freiburg
We study reactions of negative ions down to the previously unexplored temperature range below 25 Kelvin, where small molecular ions are prepared predominantly in the rovibrational ground state. Here we present recent results obtained in a temperature variable 22pole trap. Evaporation of atomic anions over the effective barrier gives insight into the stability of ion motion and allows us to determine absolute trap depths. The absolute cross section of OH− photodetachment was measured using a tomography scan and found to depend on the rotational quantum state. Proton transfer from H2 to NH2− shows an unexpected decrease in the absolute rate coefficient below 20 K indicating a very small reaction barrier. Finally, the three body association of Cl− with CH3Cl is strongly dependent on the internal structure of the stabilizing agent and shows a very strong enhancement for decreasing temperature.
In a new project we aim at interactions of trapped anions with ultracold Rubidium atoms. For this purpose we have developed a planar 32 pole ion trap on a chip; first storage results have been acchieved. The next ion trap generation will employ ITO electrodes with high optical transmission to allow laser cooling of atoms inside the ion trap.