ATOMIC CORRELATION ENERGIES FROM EFFECTIVE-CORE-POTENTIAL AND MODEL-POTENTIAL CALCULATIONS

Canonical SCF orbitals from effective-core-potential and model-potential calculations were used in CISD calculations on electron correlation energies, electron affinities, and ionization energies of fluorine, chlorine, bromine, and iodine. Results obtained with the two different pseudo-potential approaches are very close to one another in spite of richer nodal structure of the model-potential orbitals. Contamination of higher virtual model-potential orbitals by core states was found to lead to anomalous behaviour of correlation energies. © 1990.