The He–N2 anisotropic Van der Waals potential. Test of a simple model using state-to-state differential scattering cross-sections

Abstract

For He–N₂ the total and the j= 0 → 2, 1 → 3 rotationally inelastic differential cross-sections have been measured at a collision energy of E_cm= 27.3 meV and at centre-of-mass angles between 5 and 50°. These new data have been used to test the validity of an anisotropic potential recently calculated using the model of Tang and Toennies. Theoretical close-coupling cross-sections based on the potential are found to be in good agreement with the data. By studying the effect of small modifications in the potential it has been possible to estimate that the model potential predicts the anisotropy with only a negligible error but understimates the well depth of the spherical potential by ca. 20%.