Dresden 2011 – wissenschaftliches Programm

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SAMOP-DP: SAMOP Dissertation Prize 2011

SAMOP-DP 1: S-AMOP Dissertation Prize Symposium

SAMOP-DP 1.2: Hauptvortrag

Dienstag, 15. März 2011, 11:00–11:30, MENSA Dül

Manipulation of Large Neutral Molecules with Electric Fields — •Frank Filsinger — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany

For many experiments in chemistry and physics a high level of control over the external and internal degrees of freedom of the target molecules would be very beneficial. This includes, for instance, controlling the quantum state and the conformation of the molecules, as well as their spatial orientation in the laboratory frame.

Here, I will discuss how such control can be achieved using strong dc electric, ac electric, and laser fields. Conformers (structural isomers) of neutral molecules can be spatially separated with electric fields, based on their distinct dipole moment-to-mass ratios. In one setup, the conformers are separated employing ac electric fields in an alternating gradient m/µ-selector (the equivalent of the quadrupole mass filter for ions). In a second setup, conformer separation is accomplished in a Stern-Gerlach-type experiment. In this approach, a dc electric field disperses polar molecules in a supersonic jet according to their effective dipole moments µ_eff. Because molecules in the lowest rotational quantum states have the largest µ_eff and are deflected most, quantum-state selection is achieved as well. If such quantum-state-selected samples are used as targets, unprecedented degrees of laser-induced alignment and mixed-field orientation are obtained. This method is applicable to a wide range of polar molecules and should eventually enable experiments on pure samples of strongly aligned or oriented ground-state molecules offering new prospects in molecular sciences.