Electronic Charge Distributions for Heavy Ions at High Velocities

Abstract

The equilibrium electronic charge-state distributions of ${\mathrm{C}}^{12}$, ${\mathrm{N}}^{14}$, ${\mathrm{O}}^{16}$, and ${\mathrm{Ne}}^{20}$ ions in Zapon at energies between 1.59 and 10.5 MeV/nucleon are measured. The nonequilibrium charge distributions for ${\mathrm{Ar}}^{40}$ ions at 10.2 MeV/nucleon are also given. The experimental technique used makes possible measurements of charge states that comprise less than ${10}^{\ensuremath{-}5}$ of the total beam. The equilibrium charge data are satisfactorily interpreted by, and lend support to, the phenomenological theory of Dmitriev. It is found possible to present the ratio of loss to capture cross sections for the $1K$, $2K$, and $1L$ electrons and the mean ionic charge for all ions in terms of universal functions involving the ion velocity and ionic and nuclear charge. The relative values of the absolute cross sections for the loss and capture of single electrons by ${\mathrm{Ar}}^{40}$ ions are interpreted by simple statistical arguments.