B. Verhaar et al., COLD-COLLISION PROPERTIES DERIVED FROM FREQUENCY-SHIFTS IN A CESIUM FOUNTAIN, Physical review. A, 48(5), 1993, pp. 180003429-180003432
We interpret recently measured collisional frequency shifts in a cesiu
m atomic fountain using coupled-channel theory and a simple picture of
hyperfine-coupled long-range molecular states. We predict the existen
ce of Cs2 singlet and triplet states very close to threshold with an a
ssociated strong influence on ultracold collisions and large negative
values for the Cs + Cs scattering lengths. Our results are important f
or future precision experiments using Cs fountains, and may also have
important consequences for attempts to realize a Bose condensate in an
ultracold atomic Cs vapor.