Variable Phase Method Used to Calculate Ultracold Scattering Properties of 7Li33Cs

Elastic scattering properties of singlet and triplet states of ⁷Li¹³³Cs at ultralow temperatures are calculated using the constructed potential curves gleaned from high-precision spectroscopy measurement. We show how to reach the scattering length and the number of bound states via the variable phase method. The scattering lengths of the singlet and triplet states of ⁷Li¹³³Cs are 50.5 a.u. and -135.7 a.u., respectively. We derive two corrections, arising from long range interactions, accurately to at least first order, which provide upper and lower computed bounds to the scattering length. Our results are consistent with the recent experimental data and the theoretical calculation.