Electron-impact ionization of the C atom

Abstract

Time-dependent close-coupling (TDCC), $R$-matrix-with-pseudostates (RMPS), and time-independent distorted-wave (TIDW) methods are used to calculate electron-impact ionization cross sections for the carbon atom. The TDCC and RMPS results for the $1{s}^{2}2{s}^{2}2{p}^{2}$ ground configuration are in reasonable agreement with the available experimental measurements, while the TIDW results are $30%$ higher. Ionization of the $1{s}^{2}2s2{p}^{3}$ excited configuration is performed using the TDCC, RMPS, and TIDW methods. Ionization of the $1{s}^{2}2{s}^{2}2p3l$ ($l=0$--2) excited configurations is performed using the TDCC and TIDW methods. The ionization cross sections for the excited configurations are much larger than for the ground state. For example, the peak cross section for the $1{s}^{2}2{s}^{2}2p3p$ excited configuration is an order of magnitude larger than the peak cross section for the $1{s}^{2}2{s}^{2}2{p}^{2}$ ground configuration. The TDCC results are again found to be substantially lower than the TIDW results. The ionization cross-section results will permit the generation of more accurate, generalized collisional-radiative ionization coefficients needed for modeling moderately dense carbon plasmas.