Physical Review Letters
We report on the observation of ultracold heteronuclear Feshbach molecules. Starting with a 87Rb Bose-Einstein condensate and a cold atomic gas of 85Rb, we utilize previously unobserved interspecies Feshbach resonances to create up to 25,000 molecules. Even though the 85Rb gas is nondegenerate, we observe a large molecular conversion efficiency due to the presence of a quantum degenerate 87Rb gas; this represents a key feature of our system. We compare the molecule creation at two different Feshbach resonances with different magnetic-field widths. The two Feshbach resonances are located at 265.44±0.15 G and 372.4±1.3 G. We also directly measure the small binding energy of the molecules through resonant magnetic-field association.
Papp, S. B. and Wieman, C. E., "Observation of Heteronuclear Feshbach Molecules from a 85Rb – 87Rb gas" (2006). Physics Faculty Contributions. 35.