Feshbach spectroscopy and scattering properties of ultracold Li + Na mixtures

Abstract

We have observed 26 interspecies Feshbach resonances at fields up to 2050 G in ultracold 6Li+23Na mixtures for different spin-state combinations. Applying the asymptotic bound-state model to assign the resonances, we found that most resonances have d-wave character. This analysis serves as guidance for a coupled-channel calculation, which uses modified interaction potentials to describe the positions of the Feshbach resonances well within the experimental uncertainty and to calculate their widths. The scattering length derived from the improved interaction potentials is experimentally confirmed and deviates from previously reported values in sign and magnitude. We give prospects for 7Li+23Na and predict broad Feshbach resonances suitable for tuning. © 2012 American Physical Society.