Differential molecular beam scattering cross sections as a probe of the NH3-H2 potential surface

Differential cross sections have been calculated in the quantum mechanical centrifugal sudden approximation for the rotational excitation of the system NH3-H2 using three recently published potential energy surfaces. The results of the calculations are compared with measured total differential cross sections for oD2-NH3 at a collision energy E = 95.9 meV and differential energy loss spectra for NH3-oD2 at E = 118.3 meV. These data are mainly sensitive to the repulsive part of both the isotropic and the anisotropic potential. The results of the comparison indicate that all three potential surfaces are able to reproduce the total differential cross sections, while part of the energy loss spectra are not correctly predicted by one of the surfaces, indicating a too weak anisotropy