ELASTIC-SCATTERING OF 2 LI-7 ATOMS

Interaction potentials for the X 1SIGMA(g)+ and a 3SIGMA(u)+ states of Li2 are constructed and used in calculations of the elastic scatterin g of two Li-7 atoms at ultralow temperatures. The extreme sensitivity of the cross sections to the details of the interaction potentials is demonstrated. The calculated elastic and spin-change cross sections ar e very large, of the order of 10(-13) cm2 at zero temperature. The pre dicted scattering length for the triplet state is negative with a valu e of -17.2a0. Pronounced shape resonances appear at energies of 4.9 X 10(-8) a.u. in the singlet scattering and 5.5 X 10(-7) a.U. in the tri plet scattering.