Probability of Multiple Ionization by Electron Impact

Abstract

The ionization efficiency curves for the 3-fold ionization of Ar, and the 3, 4, 5, and 6-fold ionization of Xe have been examined. It is shown that, near the threshold, the probability of n-fold ionization varies as the nth power of the excess electron energy for n = 3 and 4, and probably also for n = 5 and 6. The determination of appearance potentials for such processes is discussed.