Interaction potentials and ultracold scattering cross sections for the 7Li+-7Li ion-atom system

Abstract

We calculate the isotope independent Li+-Li potential energy curves for the electronic ground and first excited states. Scattering phase shifts and total scattering cross section for the 7Li+-7Li collision are calculated with emphasis on the ultra-low energy domain down to the s-wave regime. The effect of physically motivated alterations on the calculated potential energy curves is used to determine the bound of accuracy of the low-energy scattering parameters for the ion-atom system. It is found that the scattering length for the A2Σ+u state, au = 1325 a0, is positive and has well-constrained bounds. For the X2Σ+g state, the scattering length, ag = 20465 a0 has a large magnitude as it is sensitive to the restrained change of the potential, due to the presence of a vibrational state in the vicinity of the dissociation limit.