Darmstadt 2008 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 12: Kalte Moleküle II [gemeinsam mit MO]
Q 12.1: Talk
Tuesday, March 11, 2008, 11:00–11:15, 3G
Deceleration, trapping and accumulation of NH molecules — •Steven Hoekstra, Markus Metsälä, Peter C. Zieger, Ludwig Scharfenberg, Joop J. Gilijamse, Sebastiaan Y.T. van de Meerakker, and Gerard Meijer — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
We report on the Stark-deceleration and electrostatic trapping of metastable NH molecules. Furthermore, the progress towards higher densities of cold neutral molecules by accumulation of multiple Stark-decelerated packets of NH molecules in a magnetic trap will be presented.
NH molecules in the long-lived metastable a1Δ (v=0, J=2) state are ideally suited for Stark deceleration experiments because of their relatively large Stark shift and low mass. The metastable molecules (τ > 2.7 s) are produced in a supersonic expansion with a velocity of ∼ 450 m/s, and are decelerated to a standstill by a 108-stage decelerator. Subsequently the metastable molecules are trapped electrostatically, with a temperature of about 50 − 100 mK, a density of ∼ 106 cm−3 and a 1/e trapping lifetime of 1.4 s.
Following the deceleration and trapping, the metastable NH molecules are detected by the excitation of a spin-forbidden transition, resulting in spontaneous decay to the electronic ground state (X3Σ−). The electronic ground state has a negligible Stark shift, but can be trapped magnetically. The first experiments on the accumulation of ground state NH molecules in a magnetic trap will be presented.