Analysis of Low-Energy Electron Scattering by Helium, Neon, and Argon

A least-squares method has been used to fit Ramsauer and Kollath's data on the scattering of electrons from helium, neon, and argon with a set of four phase shifts. All the known experimental points between 1.0 eV and an energy 0.6 eV below the threshold for inelastic scattering in each gas were analyzed. The effect of spin-orbit splitting on the description of the scattering has been neglected, as usual. The angular distributions and the total cross sections computed from the four phase shifts at each energy agree well with the original data, except possibly for argon, where more than four phase shifts are probably required. A graphical comparison has been made between the variation with energy of the phase shifts so determined and various recent theoretical predictions, as well as Andrick and Ehrhardt's recent direct measurements.