Electron-impact ionization of C+excited states

Abstract

Nonperturbative close-coupling and perturbative distorted-wave methods are used to calculate electron-impact ionization cross sections for excited states of C${}^{+}$. Both the time-dependent close-coupling and the time-independent distorted-wave methods are used to calculate direct ionization cross sections for the $1{s}^{2}2{s}^{2}3l$ configurations. An $R$ matrix with pseudostates method is used to calculate total ionization cross sections for the $1{s}^{2}2{s}^{2}3l$ configurations, including both direct and indirect excitation-autoionization contributions. Comparison of the results shows both a substantial reduction of the direct ionization cross sections due to nonperturbative effects and a large contribution to the total ionization cross sections due to indirect contributions coming from $2s\ensuremath{\rightarrow}2p$ excitations. The ionization cross-section results will permit the generation of more accurate generalized collisional-radiative ionization coefficients needed for the modeling of moderately dense carbon plasmas.