Coincidence electron spectroscopy of electron-impact multiple ionization of argon

Abstract

Measurements of the partial double differential ionization cross sections of argon atoms have been made by performing coincidences between recoil ions and energy- and angle-selected slow electrons produced in 12-24 keV e- -Ar collisions. Results show that the Ar3+ ions are formed mainly by a two-step-one process via electron shake-off. These measurements have enabled determination of the shake-off probability S=0.14±0.01 for L2,3 subshell, which is in good agreement with a theoretical predication. Additionally, Ar2+ and Ar+ ions are found to arise respectively from the filling of L -shell vacancy by an auger transition and from the direct ionization of M -shell of the argon atom. © 2005 The American Physical Society.