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

Electron-impact ionization cross sections are calculated for the ground and metastable states of ${\mathrm{C}}^{+}$. 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 ${\mathrm{C}}^{+}$ and approximately 15% for metastable state ${\mathrm{C}}^{+}$. Fairly small excitation-autoionization contributions are found for ground state ${\mathrm{C}}^{+}$, while larger excitation-autoionization contributions are found for metastable state ${\mathrm{C}}^{+}$. 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 ${\mathrm{C}}^{+}$ and approximately 25--35 % for metastable state ${\mathrm{C}}^{+}$. Finally, comparisons between theory and experiment find that present and previous ${\mathrm{C}}^{+}$ 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, ${\mathrm{C}}^{2+}$, and ${\mathrm{C}}^{3+}$, accurate ionization cross sections and rate coefficients are now available for the ground and metastable states of all carbon ion stages.