ACCURACY OF MOLECULAR-DATA IN THE UNDERSTANDING OF ULTRACOLD COLLISIONS

We show-through close-coupled quantum-scattering calculations that the cross section for fine-structure-changing collisions between excited P-2(3/2) and ground S-2(1/2) A atoms of the same species, where A = Rb or Cs, is very sensitive to the molecular potentials and spin-orbit m atrix elements of the alkali-metal-dimer species. Spectroscopic studie s of these species are needed to extract accurate parameters. New high -resolution photoassociation spectroscopy of trapped atoms could be us ed for this purpose.