The angular distribution of Ar + Ar scattering at E = 9.16 × 10−14 erg was measured out to the rainbow pattern (supernumerary rainbow and part of the rainbow peak) by the crossed molecular beam technique, with mass spectrometric detection. This distribution was compared to calculated differential cross sections. Total cross sections, and spectroscopic constants for Ar2 were also calculated. The trial potentials were L.J.-12,6, LJ.-20,6, a modified Lennard–Jones potential (L.J.-14,12,8,6) and the Bobetic–Barker potential. The Bobetic–Barker potential is the one most consistent with cross section and spectroscopic experiments.