2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/24305We perform an analysis of recent experimental measurements and improve the lithium interaction potentials. For $^6$Li a consistent description can be given. We discuss theoretical uncertainties for the position of the wide $^6$Li Feshbach resonance, and we present an analytic scattering model for this resonance, based on the inclusion of a field-dependent virtual open-channel state. We predict new Feshbach resonances for the $^6$Li-$^7$Li system, and their importance for different types of crossover superfluidity models is discussed.4 pages, 3 figures, revised versionStatistical MechanicsSoft Condensed Mattertext