A study of the neon–methane interaction potential as determined from low energy molecular beam experiments

Abstract

An exhaustive search of the parameter space for the Ne–CH4 interaction potential is made in an attempt to determine a potential which will reproduce the results of molecular beam scattering experiments. The experiments were performed at low energy, well below the threshold for vibrational excitation. It is shown that the effects of the long-range part of the potential were not seen in the experiment. It is further shown that the anisotropy is well represented as far as the experiments are concerned by a fourth rank expansion. In the light of this and earlier studies, it is concluded that a rigid top model for methane is not capable of describing the experimental results even though the collision energy is well below the threshold for vibrational excitation. This is in marked contrast to atom–diatomic molecule scattering.