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Published on: March 30, 2017
Deviation from universality in collisions of ultracold 6Li2 molecules
Tout T Wang1, Myoung-Sun Heo, Timur M Rvachov
1MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. tout@physics.harvard.edu
Abstract:
Collisions of 6Li2 molecules with free 6Li atoms reveal a striking deviation from universal predictions based on long-range van der Waals interactions. Li2 closed-channel molecules are formed in the highest vibrational state near a narrow Feshbach resonance and decay via two-body collisions with Li2, Li, and Na. For Li2 + Li2 and Li2 + Na, the decay rates agree with the universal predictions of the quantum Langevin model. In contrast, the rate for Li2 + Li is exceptionally small, with an upper bound 10 times smaller than the universal prediction. This can be explained by the low density of available decay states in systems of light atoms [G. Quéméner, J.-M. Launay, and P. Honvault, Phys. Rev. A 75, 050701 (2007)], for which such collisions have not been studied before.
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