Sympathetic cooling of ⁶Li atoms

We use recently measured cold photoassociation and two-photon data to extract the singlet and triplet accumulated radial phases of interacting ground-state lithium atoms. Using the resulting values we predict scattering lengths, Feshbach resonances, and exchange decay rates for cold collisions between ⁷Li and ⁶Li atoms that are of interest for the possibility of sympathetic cooling of ⁶Li and for the coexistence of the bosonic and fermionic quantum-degenerate phases of ⁷Li and ⁶Li. In addition, we calculate scattering lengths and exchange decay rates for cold collisions between identical lithium isotopes in different hyperfine states. These quantities are used to examine the possibilities of coexisting ⁷Li Bose condensates and of evaporatively cooling coexisting ⁶Li subsystems.