Calculation of Elastic Scattering Properties in an Ultra-Cold ⁸⁵Rb--⁸⁵Rb Vapour

We report the calculation of the same-species elastic scattering properties for the ultracold rubidium--rubidium (⁸⁵Rb--⁸⁵Rb) system and the results are compared with other theoretical and experimental results in detail. We present an improved potential for triplet ground states of the Rb₂ molecule, and calculate the scattering lengths a_t and the effective range r₃ using WKB and Numerov methods for two rubidium-85 collisions in the triplet state. Also, we investigate the convergence of these scattering properties, i.e. the dependence on core radius and K⁰ parameter using quantum defect theory and the analytic calculations of scattering length obtained by Szmytkowski. In addition, we present evaporative cooling and other results that include phase shift and cross section at zero energy limit.