Abstract
MCHF n-expansion procedures are applied to the Be and Li- 1s22s2 1S ground state. Up to n=5 all configuration states are included. From n=6 results, a pattern was observed for triple and quadruple excitations and this pattern was then applied to the higher n. Calculations were performed up to n=10. For Be, the extrapolated total energy of -14.667314 Hartree and the double ionization energy of 1.011796 Hartree agree well with the predicted exact non-relativistic energies. An ab initio value of the quantity related to the Be 2s2-Be+ 2s specific mass shift is reported for the first time. The electron affinity for Li is predicted to be 0.6176 eV. Both of these values are in excellent agreement with experiment.