Elastic Scattering of Ultracold 23Na and 39K Atoms in the Singlet State

The elastic scattering properties for collisions between ultracold ²³Na and ³⁹K atoms in the singlet state are investigated. Based on the recent theoretical and experimental results, the improved hybrid potential is presented for the singlet X¹Σ_g⁺ ground state of NaK. By means of the Numerov and semiclassical methods, the values of the s-wave scattering length a for the singlet state are calculated to be 33.3757a₀ and 37.9399a₀, respectively. Pronounced shape resonances appear for the l = 1 partial wave for the X¹Σg⁺ state. In addition, the s-wave scattering cross section, total cross section and energy positions of shape resonances for the X¹Σ_g⁺ state are discussed.