Core pseudopotential valence electron calculations on diatomic molecules containing second-row atoms

Abstract

A valence-electron-only model potential (VEOMP) method has been incorporated in the GAUSSIAN 70 program. The method is tested by calculations of the orbital energies and equilibrium bond lengths of the multiply-bonded diatomic molecules CO, CS, SiO and SiS using both the STO–3G and STO–6G minimum basis sets. The VEOMP procedure shows a uniform performance for both first- and second-row atoms. A comparison of CS with CH₂S and CH₃SH indicates that the VEOMP procedure accurately reflects the change in molecular structure within this series.