State-dependent associative ionization in xenon

Abstract

A simple qualitative explanation is presented for the observed state selectivity in the associative ionization of ${\mathrm{Xe}}^{*}(nf)$ to form ${\mathrm{Xe}}_{2}^{+}.$ It is suggested here that compared to electrons in ${\mathrm{Xe}}^{*}(\mathrm{np})$ Rydberg states, electrons excited to nf levels are radially localized outside the ${\mathrm{Xe}}^{+}$ ion core for long periods of time due to a larger centrifugal barrier in the effective atomic potential. This enhances the probability that excited Xe atoms in an f state will encounter a ground-state atom at those impact distances that lead to the formation of dimer ions.