Parameters for Cold Collisions of Lithium and Caesium Atoms

We calculate the s-wave scattering length and effective range and the p-wave scattering volume for ⁷Li atoms interacting with ¹³³Cs atoms via the X¹Σ⁺ molecular potential. The length and volume are found by fitting the log-derivative of the zero energy wave function evaluated at short range to a long range expression that accounts for the leading van der Waals dispersion potential and then incorporating the remaining long range dispersion contributions to first order. The effective range is evaluated from a quadrature formula. The calculated parameters are checked from the zero energy limits of the scattering phase shifts. We comment on ill-conditioning in the calculated s-wave scattering length.