Low-energy electron scattering by atomic carbon

Matrix variational calculations of electron scattering by atomic C have been carried out, including target atom configurations $2s^{2}2p^2$, $2s2p^3$, and $2p^4$ 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 $n=3\mathrm{}$ excitation threshold. In the lowest energy range, scattering is dominated by a ${}_{}{}^2{}_{}{}^{}P_{}^o{}_{}{}^{}$ 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 ${}_{}{}^2{}_{}{}^{}D_{}^o{}_{}{}^{}$ state of ${\mathrm{C}}^{-}$ at its experimental position, just below the neutral ground state. Estimates are given of the rate constants for deactivation of the ${}_{}{}^1{}_{}{}^{}D$, ${}_{}{}^1{}_{}{}^{}S$, and ${}_{}{}^5{}_{}{}^{}S_{}^o{}_{}{}^{}$ states by thermal electrons.