Feshbach spectroscopy of an ultracold mixture of $^{85}$Rb and   $^{133}$Cs
  We report the observation of interspecies Feshbach resonances in an optically trapped mixture of $^{85}$Rb and $^{133}$Cs. We measure 14 interspecies features in the lowest spin channels for a magnetic field range from 0 to 700 G and show that they are in good agreement with coupled-channel calculations. The interspecies background scattering length is close to zero over a large range of magnetic fields, permitting the sensitive detection of Feshbach resonances through interspecies thermalisation. Our results confirm the quality of the Rb-Cs potential curves and offer promising starting points for the production of ultracold polar molecules. 
Hung-Wen Cho, Daniel J. McCarron, Michael P. Koppinger, Daniel L.   Jenkin, Kirsteen L. Butler, Paul S. Julienne, Caroline L...
physics.atom-ph