Heidelberg 2015 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 13: Collisions & Energy Transfer

MO 13.3: Vortrag

Mittwoch, 25. März 2015, 11:45–12:00, PH/SR106

Dissociative Recombination measurements of SH⁺ — •Arno Becker¹, Christian Domesle¹, Wolf Geppert², Claude Krantz¹, Oldřich Novotný^1,3, Daniel Savin³, Dirk Schwalm^1,4, Bian Yang⁵, and Andreas Wolf¹ — ¹Max-Planck-Institut für Kernphysik, Heidelberg — ²Stockholm University, Stockholm, Sweden — ³Columbia Astrophysics Laboratory, New York, USA — ⁴Weizmann Institute of Science, Rehovot, Israel — ⁵Chinese Academy of Sciences, Lanzhou, PRC

Astrophysicists observe trace molecules to investigate the properties of interstellar medium. SH⁺ is believed to be a very efficient probe for energetic interstellar environments, such as shocked gas. To interpret the observations, however, the models need reliable experimental data on dissociative recombination (DR) of SH⁺.

To this end we have experimentally investigated DR of SH⁺ at the Test Storage Ring (TSR) of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. An SH⁺ beam was merged with a cold electron beam produced by a photo-cathode. Utilizing an energy sensitive Si detector, recombination rate coefficients were determined for collision energies ranging from sub-meV up to 6 eV, covering kinetic temperatures down to 10 K. Moreover, we have determined branching ratios for various product excitation states utilizing a position sensitive microchannel plate detector. Here, we have employed a novel approach requiring detection of only one fragmentation partner. The method will be a valuable tool for analyzing imaging data of the heavier molecules to be stored in the upcoming Cryogenic Storage Ring (CSR).