Correlation Energy in Atomic Systems. IV. Degeneracy Effects

Abstract
The degeneracy effects in the isoelectronic series of the first‐row atoms are analyzed. The near‐degenerate configurations 1s22s22p2 and 1s22s02pn+2 are computed within the framework of a two‐configuration SCF technique. The newly obtained correlation energy diagram indicates a remarkable simplicity in its structure.