Calculation of the Electron Affinity of Boron

Ab initio calculations have been made for the ground states of neutral B and ${\mathrm{B}}^{-}$ using configuration-interaction wave functions which included the Hartree-Fock configuration, single excitations, and double excitations of the types ($1s,2p$), ($2s,2s$), ($2s,2p$), and ($2p,2p$). These calculations indicate that ${\mathrm{B}}^{-}$ is stable and that the electron affinity of B is 0.0028 Hartrees (0.08 eV). Contributions from the omitted types of correlations were investigated by making separate-pair calculations for the ($1s,1s$) and ($1s,2s$) pairs. These contributions do not affect the qualitative conclusions. Consideration of the probable errors in the calculations leads to the definite conclusion that ${\mathrm{B}}^{-}$ is stable and to an estimate of 0.25 eV for the electron affinity of boron.