Photoelectron angular distributions from electron-atom collisions

The differential cross section for electron-impact ionization of atoms has been derived for the general case and the dipole (E 1) limit of the Born approximation. Emphasis was placed on the theoretical description of the (e,2e) angular correlation between fast electrons scattered in the forward direction and electrons ejected by the ionization process. The general angular-momentum treatment of this work results in a more complete description of the dipole (e,2e) angular distribution than previous purely kinematic analyses.