Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 34: Cold Molecules II
Q 34.5: Vortrag
Mittwoch, 16. März 2011, 15:30–15:45, BAR Schön
The alternating-gradient m/µ-selector — •Stephan Putzke1, Frank Filsinger1, Jochen Küpper1,2,3, and Gerard Meijer1 — 1Fritz-Haber-Institut der MPG, Berlin — 2Center for Free-Electron Laser Science, DESY, Hamburg — 3Universität Hamburg
Over the last years we have developed and applied methods for the manipulation of the motion of large and complex molecules. Because all states are high-field seeking at the relevant field strengths, alternating gradient (dynamic) focusing has to be applied [1]. Polar molecules in different quantum states or conformers, exhibiting a sufficently different Stark effect, can be filtered selectively. This method has been succesfully used for the conformer selection of 3-aminophenol in a m/µ-selector [2]. The resolution can be improved by changing the duty-cycle of the half-periods in the switching cycle [3].
Here we present results obtained with a newly set up second generation AG guide. We investigate the transmission of individual rotational quantum states of benzonitrile (C7H5N), a prototypical large polar molecule. The transmission and the m/µ-resolution are considerably improved by the new setup. It employs both, longer electrodes – allowing more switching cycles – and an improved alignment. It now becomes possible to filter almost all quantum states out of the beam and to prepare a nearly pure ground-state sample of benzonitrile.
[1] D. Auerbach et al., J. Chem. Phys. 45, 2160 (1966); H. L. Bethlem
et al., J. Phys. B 39, R263 (2006)
[2] F. Filsinger et al., Phys. Rev. Lett. 100, 133003 (2008)
[3] F. Filsinger et al., Phys. Rev. A 82, 052513 (2010)