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MO: Molekülphysik

MO 57: Poster: Cold Molecules

MO 57.10: Poster

Donnerstag, 16. März 2006, 16:30–18:30, Labsaal

Influence of tight traps on photoassociation in ultracold alkali gases — •Sergey Grishkevich and Alejandro Saenz — AG Moderne Optik, Institut für Physik, Humboldt-Universität zu Berlin, Hausvogteiplatz 5-7, 10117 Berlin

The influence of tight harmonic traps on the photoassociation process in ultracold alkali gases is investigated. As a model system, Li atoms are considered with realistic interatomic interaction potentials. It is demonstrated that the simple rule "tighter trap leads to higher photoassociation rates" as one would expect from a simple spatial-confinement argument is not applicable for all final states. In fact, it is inapplicable for those states with the highest photoassociation rate in the trap-free case. This is in agreement with a general sum rule that can be derived and shows that the sum of the rates to all final states is in fact (almost) independent of the tightness of the trap. The findings for Li atoms are generalized by considering different atomic species as well as artificially modified scattering lengths (as may be implemented by Feshbach resonances). Furthermore, the validity of the usually adopted pseudo-potential approximation (substituting the correct interatomic potential) for describing photoassociation is discussed.