Abstract
Wavefunctions for the ground states of the atoms Be to F, consisting of the dominant configuration and selected singly excited configurations, are obtained by a multi configuration method which is based on the generalized Brillouin theorem. Energy lowerings relative to the restricted Hartree-Fock (HF) energy are discussed and compared with maximally-paired HF, unrestricted HF, GF and first-order results. The increasing importance of p-shell correlation is demonstrated.