Nonrelativistic energy of the ground state ofLi−and the electron affinity of lithium

The energy results of an extensive configuration-interaction calculation of the ground state of ${\mathrm{Li}}^{-}$ are reported. A quantitative assessment of all sources of truncation errors leads to a nonrelativistic energy estimate of -7.5004 ± 0.0002 a.u. An $r_{ij}$ calculation on the ground state of ${\mathrm{Li}}^{-}$ yields a rigorous upper bound to the nonrelativistic energy of -7.500 186 a.u., in excellent agreement with the estimate from the configuration-interaction calculation. Consideration of relativistic contributions to the electron affinity of Li leads to an estimate of the electron affinity of Li of 0.609 ± 0.007 eV.