ELASTIC-SCATTERING OF 2 NA ATOMS

Interaction potentials for the X g+1 and a u+3 states of Na2 are constructed and used in calculations of the elastic scattering of two Na atoms at ultralow temperatures. The sensitivity to retardation effects (or Casimir corrections) is explored. The calculated elastic and spin-change cross sections are very large, of the order of 10-1210-13 cm2 at zero temperature. The predicted scattering lengths are both positive, 34.9 a0 for the X g+1 state and 77.3 a0 for the a u+3 state. Pronounced shape resonances appear for the l=3 and 7 partial waves for the singlet and l=6 for the triplet states. © 1994 The American Physical Society.