Berlin 2014 – scientific programme
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MO: Fachverband Molekülphysik
MO 13: Posters 3: Cold Molecules, Helium Nano Droplets, and Experimental Techniques
MO 13.14: Poster
Wednesday, March 19, 2014, 16:30–18:30, Spree-Palais
Detecting the Rotational State of Electrically Trapped Polyatomic Molecules — •Rosa Glöckner, Alexander Prehn, Martin Zeppenfeld, and Gerhard Rempe — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching
The determination of the internal state of molecules is a key element for their precise control. However, especially for polyatomic molecules, state sensitive detection can be a considerable challenge due to predissociation and fragmentation when addressing electronic transitions with uv light. We present here an alternative for trapped molecules using depletion.
Our method is based on the difference of signals with and without depletion: driving transitions from selected rotational states to untrapped states.
Therefore, the detection of the molecule itself can be state independent and thus a simple method like a quadrupol mass spectrometer (QMS) is sufficient. We demonstrate two variations of the method, infrared depletion and microwave depletion, and discuss the assets and drawbacks.
In addition to rotational J-levels, we can address individual M-sublevels. Using this we can extract the narrow field distribution in our homogeneous-field electric trap[1] by measuring the Stark-broadened line shape of the transition between the |J=3,K=3,M=3⟩ → |J=4,K=3,M=4 ⟩ states of CH3F. We expect our method to work for a large number of molecular species.
[1] B.G.U. Englert et al., Phys. Rev. Lett. 107, 263003 (2011).