Low-energy electron scattering by atomic carbon

Matrix variational calculations of electron scattering by atomic C have been carried out, including target atom configurations 2s²2p², 2s2p³, and 2p⁴ and all possible single virtual excitations of the $2p$ orbital. Total and differential elastic and inelastic cross sections are reported for energies below the first $n=3$ excitation threshold. In the lowest energy range, scattering is dominated by a ²Pᵒ shape resonance. The position of this resonance, which is sensitive to small differences of electronic correlation energy, is parametrized by a net correlation energy parameter whose value is chosen to place the ²Dᵒ state of C^- at its experimental position, just below the neutral ground state. Estimates are given of the rate constants for deactivation of the ¹D, ¹S, and ⁵Sᵒ states by thermal electrons.