2010/09/30 by Christoph Strauss, Tetsu Takekoshi, Florian Lang +4 · 1 citation
Physics and Astronomy · #physics.atom-ph #cond-mat.other
paper · pdf · doi:10.1103/physreva.82.052514
published as Phys. Rev. A 82, 052514 (2010)
arxiv created 2010/10/14 · arxiv updated 2011/07/18
We have performed high-resolution two-photon dark-state spectroscopy of an ultracold gas of Rb molecules in the triplet ground state at a magnetic field of about 1000 G. The vibrational ladder as well as the hyperfine and low-lying rotational structure is mapped out. Energy shifts in the spectrum are observed due to singlet-triplet mixing at binding energies as deep as a few hundred GHz x h. This information together with data from other sources is used to optimize the potentials of the triplet and singlet states in a coupled-channel model. We find that the hyperfine structure depends weakly on the vibrational level. This provides a possible explanation for inaccuracies in recent Feshbach resonance calculations.