Wavefunctions and Correlation Energies for Two‐, Three‐, and Four‐Electron Atoms

A recently developed method (the GF method) which is equivalent to optimizing the orbitals of a Slater determinant after spin projection has been applied to H^−, He, Li^+, Be^++, Li, Be^+,B^++, Li^−, Be, B^+ and C^++. These wavefunctions, which can be given an independent particle interpretation, yield better energies than those of the Hartree‐Fock method. For example, H^− and Li^− are correctly predicted to be stable in contradistinction with the Hartree‐Fock results. The new correlation energies are tabulated and compared to the Hartree‐Fock values. In the case of the two‐electron systems the new wavefunctions are nearly at the radial limit, accounting for 93% to 97% of the radial correlation error present in the Hartree‐Fock description.