Multiple Photo-Ionization of Xenon

Abstract

The photoionization cross sections for the production of ${\mathrm{Xe}}^{+}$, ${\mathrm{Xe}}^{++}$, and ${\mathrm{Xe}}^{+++}$ have been measured in the energy range 28-83 eV. At energies between the thresholds for ${\mathrm{Xe}}^{++}$ production 33.3 eV and $4d$-electron removal 67.55 eV, the ${\mathrm{Xe}}^{++}$ cross section reaches about one-third of the total cross section. This cannot be accounted for by an independent electron model in terms of an electron shake-off process. At energies greater than 67.55 eV, both the ${\mathrm{Xe}}^{+}$ and ${\mathrm{Xe}}^{++}$ cross sections increase; here the singly charged ion should be accompanied by fluorescence and the doubly charged ion can result from a simple Auger process. The triple ionization is attributed to a process which involves first the removal of a $4d$ electron and then an Auger event in which two electrons are emitted simultaneously.