Theoretical triply differential cross section of electron-impact ionization of atoms

Abstract

The triply differential cross section of the electron-impact ionization of atoms is given in a parametrized form, suitable for theoretical computations or for semiempirical fittings. Application of the present formulation is demonstrated. Merits of coplanar measurements are discussed. It is also shown that the coplanar up-down asymmetry of the ejected electron is linear in the scattering angle, or the momentum transfer, of the incident electron for small momentum transfers.