Frankfurt 2006 – scientific programme
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MO: Molekülphysik
MO 52: Cold molecules I
MO 52.4: Talk
Thursday, March 16, 2006, 11:40–11:55, H10
An AC electric trap for molecules in high-field seeking states — •Jacqueline van Veldhoven1, Hendrick L. Bethlem1,2, Melanie Schnell1, and Gerard Meijer1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany — 2Laser Centre Free university, Amsterdam, the Netherlands
The absolute ground state of any molecule is high-field seeking. It is therefore very important to develop deep traps with large volumes for molecules in high-field seeking states. Only ground state molecules can be evaporatively cooled, as trap loss due to inelastic collisions is avoided. Furthermore, only traps for molecules in high-field seeking states can be used to trap heavier molecules with small rotational constants.
A maximum of the static electric field in free space can be created in one or two dimensions only. In a cylindrically symmetric geometry, for instance, a static electric field can be made with a maximum in the radial and a minimum in the axial direction, or vice versa. Switching between these two saddle point configurations results in a field that is alternately focusing and defocusing in each direction for molecules in high-field seeking states. At the right switching frequency the overall effect is focusing, and confinement in three dimensions can thus be obtained.
We here report on the trapping of ammonia molecules in both high-field and low-field seeking states in such a novel AC electric trap. We have studied the stability of the AC electric trap as a function of switching frequency, and we have characterized the spatial distribution and the temperature of the trapped cloud of molecules [1].
[1] J. van Veldhoven, H.L. Bethlem and G. Meijer, PRL94, 083001 (2005).