s-wave and p-wave scattering in a cold gas of Na and Rb atoms

Using improved experimentally based (XI)-I-1 (+) pound and a(3)I (+) pound molecular potentials of NaRb, we apply the variable phase method to compute new data for low energy scattering of Na-23 atoms by Rb-85 atoms and Rb-87 atoms. These are the scattering lengths and volumes, numbers of bound states and effective ranges, which we use to obtain the low energy spin-change cross section as functions of the system temperature and the isotope masses. From an analysis of the contributions of s-wave and p-wave scatterings to the elastic cross section we estimate temperatures below which only s-wave scattering is dominant. We compare our quantal results to data obtained from the semiclassical approximation. We supply evidence for the existence of a near zero energy p-wave bound state supported by the singlet molecular potential.