Radiative Absorption Cross Section of an Electron in the Field of an Argon Atom

The results of a numerical calculation of the radiative absorption cross section for an electron in the field of a neutral argon atom are reported. The atomic potential used is the same as used by Holtsmark in his treatment of the Ramsauer effect. The light frequency is 4.318×{}10¹⁴ cps. This exact cross section is compared with three approximations which contain the phase shifts for elastic scattering. One of these approximations, the one due to Holstein, is found to differ very little from the exact cross section over a large range of initial electron energies.