Photoionization cross section of theP3ground state of neutral carbon

Many-body perturbation theory is used to calculate the photoionization cross sections of the $2p$ and $2s$ subshells of the ${}_{}{}^3{}_{}{}^{}P$ ground state of neutral carbon. Resonances due to the $1s^{2}2s2\mathrm{}{p}^{2}np$ autoionizing configurations and two-electron resonances from the $1s^{2}2s^{2}3s3\mathrm{}p$ and $1s^{2}2s^{2}3p3\mathrm{}d$ configurations were calculated. Detailed agreement is obtained with the experimental data of Esteva, Mehlman-Balloffet, and Romand.