Scattering of High-Velocity Neutral Particles. XIII. Ar–CH4; A Test of the Peripheral-Force Approximation

Collision cross sections have been measured for argon atoms with energies between 700 and 2100 eV, scattered in room-temperature methane. The results have been analyzed to obtain the average potential between an argon atom and a methane molecule, 〈V(r)〉Av=936/r7.85eV, 2.31 Å≤r≤2.66 Å.This result has been used as a test of combination-rule approximations by comparing it with the average potential calculated from previous measurements on He–CH4, He–He, and Ar–Ar. The peripheral-force approximation gives consistent relations among the experimental results for these systems.