(e,3e) observation of the angular correlation between ejected and Auger electrons in the double ionization of magnesium

Electron-impact excitation of the L2,3{M}₁M₁ Auger process in magnesium has been observed in a triple-coincidence experiment. A 3.5-keV incident electron is used and the scattered electron, the ejected 2p electron, and the 35-eV Auger electron are detected. The experiment was performed for ejected electron energies of 35, 45, and 100 eV. Three-dimensional angular distributions for the ejected and Auger electrons were recorded for a fixed scattered-electron direction. A model is presented which describes the angular distribution by additive terms representing the anisotropy in the distribution of ejected and Auger electrons relative to the momentum transfer direction, and the angular correlation between the ejected and Auger electrons. Three corresponding parameters are extracted from the data and compared with the results of a calculation based on a two-step model of ionization and Auger emission.