Darmstadt 2008 – scientific programme

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MO: Fachverband Molekülphysik

MO 8: Kalte Moleküle I (gemeinsam mit Q)

MO 8.5: Talk

Tuesday, March 11, 2008, 09:45–10:00, 3G

Guiding and decelerating polar molecules above a microstructured electrode array — •Samuel A. Meek, Hendrick L. Bethlem, Horst Conrad, and Gerard Meijer — Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin

The feasibility of manipulating polar molecules by means of inhomogeneous electric fields has been successfully demonstrated by various devices, such as Stark decelerators, electrostatic traps and storage rings. While previous electrode configurations at the mm scale require potential differences of tens of kV at the electrodes, similar fields can be produced between 10µm-sized electrodes using potentials of hundreds of volts. Here, we present an electrostatic decelerating and trapping device consisting of a periodic array of 1254 microstructured linear electrodes deposited on a planar glass substrate. Application of harmonic waveforms to periodic groups of six electrodes forms a series of periodic minima which move along the array in a continuous manner without changing their distances above the electrodes. Deceleration is achieved by linearly reducing the frequency of the applied waveforms.

First experiments have been performed using a supersonic beam of a³Π₁ CO, which has a lifetime of 2.6 milliseconds. Molecules are excited with a laser directly after the nozzle and later detected using Auger deexcitation at a gold surface. TOF spectra clearly demonstrate the velocity-selective guiding of CO*, with guided velocities proportional to the frequency of the applied waveforms. First results of decelerating the CO* molecules by linearly decreasing the frequency of the waveforms, i.e. velocity of the minima, are also presented.