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Q: Fachverband Quantenoptik und Photonik

Q 56: Poster IV

Q 56.25: Poster

Donnerstag, 5. März 2009, 16:30–19:00, VMP 9 Poster

Charge exchange reactions between trapped laser-cooled barium ions and hot neutral alkali atoms — •David Offenberg, Christian Wellers, Tobias Schneider, Bernhard Roth, and Stephan Schiller — Institut für Experimentalyphsik, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany

We have studied charge exchange reactions between laser-cooled Ba⁺ ions stored in a linear quadrupole trap and neutral alkali atoms (M) evaporated from alkali metal dispensers. The charge exchange reaction Ba⁺ + M → Ba + M⁺ has not been observed for Li and Na. For K, Rb, and Cs it is clearly observed, leading to an accumulation and sympathetic cooling of the produced K⁺, Rb⁺, and Cs⁺ ions in the ion trap and causing characteristic deformations of the Ba⁺ ion ensembles’ spatial distribution. Via their Coulomb interaction with the laser-cooled Ba⁺ ions, the alkali ions are cooled to temperatures of a few ten mK. The accumulation of cold Cs⁺ ions has been characterized in terms of numbers and their translational temperatures by comparing experimentally acquired images of the Ba⁺/Cs⁺ ion ensembles with those from molecular dynamics simulations [1]. The K⁺ and Rb⁺ ions have been identified via an excitation of their specific motional resonances and making use of a mass-to-charge ratio selective extraction of the ions from the trap [2].

[1] C. B. Zhang et al., Phys. Rev. A 76, 012719 (2007)

[2] D. Offenberg et al., to appear in J. Phys. B, arXiv:0810.5097v2