Ab initiocalculation of Feshbach resonances in cold atomic collisions:s- andp-wave Feshbach resonances inL6i2

Abstract

We present a model applicable to cold diatomic collisions and solve the close-coupled equations for the particular ${^{6}\text{L}\text{i}}_{2}$ system. Feshbach resonances are determined ab initio for both $s$ and $p$ waves. The $s$-wave scattering lengths are reported for all possible hyperfine states as a function of magnetic field strengths between 0 and 1500 G. In addition, $p$-wave scattering lengths are calculated for selected hyperfine states. Matrix elements for the hyperfine, Zeeman, and rotational Hamiltonian were worked out by the use of the molecular Hund's case (a) basis set. All relevant matrix elements are reported. The short-range hyperfine interaction has been included in the calculations, and its effect on the scattering length are investigated. Hyperfine parameters were obtained from separate ab initio calculations.