Electron-impact ionization of C+ in both ground and metastable states

Abstract

Electron-impact ionization cross sections are calculated for the ground and metastable states of C+. Comparisons between perturbative distorted-wave and nonperturbative time-dependent close-coupling calculations find reductions in the peak direct ionization cross sections due to electron coupling effects of approximately 5% for ground state C+ and approximately 15% for metastable state C+. Fairly small excitation-autoionization contributions are found for ground state C+, while larger excitation-autoionization contributions are found for metastable state C+. Comparisons between perturbative distorted-wave and nonperturbative R -matrix with pseudostates calculations find reductions in the peak total ionization cross sections due to electron coupling effects of approximately 15-20% for ground state C+ and approximately 25-35% for metastable state C+. Finally, comparisons between theory and experiment find that present and previous C+ crossed-beam measurements are in excellent agreement with ground state nonperturbative R -matrix with pseudostates calculations for total ionization cross sections. Combined with previous non-perturbative calculations for C, C2+, and C3+, accurate ionization cross sections and rate coefficients are now available for the ground and metastable states of all carbon ion stages. © 2008 The American Physical Society.