Analysis of experimental total differential scattering data of nonspherical molecules with anisotropic potentials. Application to Ar–CO2

Abstract

The analysis of total (unresolved in velocity) laboratory differential cross sections with the infinite order sudden approximation is investigated in the case of significant velocity changes. Well position anisotropies of the potential, which in the center of mass system do not affect the rainbow structure, do so in the laboratory system. The rainbow structure is damped and shifted. In averaging over experimental conditions, it is necessary to include the rotational temperature of the molecule beam. Ar–CO₂ total differential scattering data are compared with calculations based on published potentials. From these comparisons we infer that the well depth anisotropy is weak. Central field calculations show that this type of analysis does not yield the spherically symmetric part of the full anisotropic potential, but a potential with a well depth approximately equal to the well depth averaged over the cosine of the body‐fixed angle of orientation.