The methane-methane total differential scattering cross section

An in-plane crossed molecular beam apparatus has been used to measure the methane-methane total differential scattering cross section. A clearly resolved rainbow oscillation enables an effective isotropic well depth to be determined rather accurately. The data is analysed using a number of spherical and anisotropic potential functions and is also fitted to an analytic semiempirical spherical model. None of the potentials currently in the literature give scattering cross sections and second virial coefficients which are in good agreement with experimental data.