Accurate calculation of the elastic scattering properties of Li-7 atoms at ultralow temperatures

摘要

The elastic scattering properties for collisions between two Li-7 atoms are investigated in the cold and ultracold regimes separately. Based on recent theoretical and experimental results, we present the improved hybrid potentials for the singlet X-1 Sigma(+)(g) and triplet a(3) Sigma(+)(u) ground states of the Lie. Our calculated values for the scattering lengths a and the effective ranges r(e) are compared with previous ones, and found them to be in good agreement. The scattering lengths are 34.6a(0) for the singlet state and -27.6a0 for the triplet state. Shape resonances occur in the collisions at low energies. We also calculate the total cross sections and the energy positions of shape resonances for both X-1 Sigma(+)(g) and a(3) Sigma(+)(u) states.