Low-Energye−-Ar Total Scattering Cross Sections: The Ramsauer-Townsend Effect

Abstract

The Ramsauer technique has been used to measure absolute total $e^{-}$-Ar scattering cross sections from 0.1 to 21.6 eV with an estimated probable error of ±3%. A phase-shift analysis of the data (for the $l=0, 1, 2$ partial waves) has been made using "modified effective range" theory which yields a scattering length of -1.65 $a_0$ and a minimum total cross section of 0.125 ${\mathrm{\AA }}^2$ at 0.285 eV.