Berlin 2001 – scientific programme
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Q: Quantenoptik
Q 17: Poster: Cooling and Trapping
Q 17.30: Poster
Wednesday, April 4, 2001, 12:30–15:00, AT2
Investigation of long range states of highly excited molecules - a scheme to create cold Na2 molecules? — •Tanja Laue, Christian Samuelis, Horst Knöckel, and Eberhard Tiemann — SFB 407, Institut für Quantenoptik, Universität Hannover
Laser cooling of atoms is a well established technique to reach sub mK
temperatures. But the extension to molecules is generally not posssible.
One way to create cold ground state molecules is photoassociation of cold
trapped atoms. Two colliding atoms absorb a photon and create an excited
molecule at long range. The de-excitation leads back to two atoms with
changed
kinetic energy but also to a small fraction of cold ground state molecules.
The formation of these cold molecules is quite efficient if the excited
molecular state has a good Franck-Condon overlap with ground state wave
functions. This can be the case for excited states with a double well
structure (example: Cs2 [1]).
A calculation for Na2 [2] shows that such a double-well potential
(6 1Σg+) which correlates to the 3s+5s asymptote exists. We setup
a
molecular beam experiment where we prepare long range molecules in the
A 1Σu+ via Franck-Condon pumping [3] and then use a coherent
process
to excite to the second well of the 6 1Σg+ state.
The status of the experiment will be presented.
[1] A. Fioretti, D. Comparat, A. Crubellier, O. Dulieu, F. Masnou-Seeuws, and P. Pillet, Phys. Rev. Lett. 80, 4402 (1998)
[2] M.-L. Almazor, O. Dulieu, M. Elbs, E. Tiemann, and F. Masnou-Seeuws, Eur. Phys. J. D 5, 237 (1999)
[3] E. Tiemann, H. Knöckel, H. Richling, Z. Phys. D 37, 323 (1996)