Stuttgart 2012 – scientific programme

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MO: Fachverband Molekülphysik

MO 21: Poster 3: Cluster, Collisions, Energy Transfer, Photochemistry, Spectroscopy in He-Droplets

MO 21.4: Poster

Thursday, March 15, 2012, 16:30–19:00, Poster.IV

Thermalization of cluster ions in a radio frequency ion trap — Raphael Präg, •Adam Piechaczek, and Bernd V. Issendorff — Fakultät für Mathematik und Physik, Universität Freiburg, Stefan-Meier Str.19, 79104 Freiburg

Calorimetric studies of free, size-selected cluster ions are performed in our group. Charged clusters are temperature controlled, transferred into high vacuum, mass-selected, and photo-fragmented by a laser pulse. The recorded fragment mass spectra are sensitive to the inner energy of the thermalized clusters, which allows us to link temperature and energy and thus deduce caloric curves. In the past a temperature controlled flow tube was used for the thermalization of the clusters. After replacing it with an radio frequency ion trap, it was important to make sure that the ions are fully thermalized in the trap. The thermalization time of water cluster ions in the radio-frequency ion-trap is examined by trapping the ions for different defined intervals before they are photo-fragmented and the fragments are analyzed. This was carried out for two different temperatures of the heat bath and the experimental results are compared to a simulation.