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A: Fachverband Atomphysik
A 26: Posters: BECs, ultracold gases and plasmas
A 26.1: Poster
Thursday, March 13, 2008, 16:30–18:30, Poster C3
Cold collisions of K atoms studied by precision spectroscopy — Stephan Falke1,2, Matthias Riedmann1, Jan Friebe1, Horst Knöckel1, Eberhard Tiemann1, and •Christian Lisdat1,3 — 1Institut für Quantenoptik, Leibniz Universität Hannover — 2Department of Physics, Yale University, New Haven, U.S.A. — 3Physikalisch-Technische Bundesanstalt Braunschweig
The interaction in ultracold thermal and quantum degenerate atomic clouds are dominated by binary collisions. Precisely these interactions make ultracold atoms the interesting field of research they are, since they determine BEC properties, produce Feshbach resonances, or allow forming molecules. All these points are closely related to the interaction potential of two colliding atoms. We report our laser-spectroscopic investigation of the least bound levels in the ground state X 1Σg+ of 39K2 undertaken on a molecular beam [1]. We measured in a two-laser lambda scheme energy differences of ground state levels in the order of 1 250 cm−1 with a precision better than 5 MHz applying a femtosecond frequency comb and iodine lines for frequency calibration. Precise models of the interaction potentials allow for an accurate description of cold collisions, e.g., Feshbach resonance positions. In a further step of the experiment we will test the precision of the mass-scaling to other isotope combinations based on the Born-Oppenheimer approximation using the isotopomere 39K41K, which is sufficiently abundant for observation in a molecular beam based on a natural potassium [1].
[1] J. Chem. Phys. 125, 224303 (2006), Phys. Rev. A 76, 012724 (2006).