A DPF data analysis yields accurate analytic potentials for Li2a3Σu+ and Li213Σg+ that incorporate 3-state mixing near the 13Σg+ state asymptote

► Accurate potentials for the two lowest triplet states of Li2 are reported. ► The MLR form works very well despite a ∼5200 cm−1 gap in experimental data. ► The MLR form is able to describe a state that couples to two others at long-range. ► For the first time, a DPF analysis involving three states simultaneously is performed. ► The best fits are with C3 lower than expected, a fit with more data might be better.