VESCF-MO studies of molecules containing atoms from the second row of the Periodic Table. II. Properties of the fluorides of silicon, phosphorus, sulphur, and chlorine for a minimal basis set excluding 3d-orbitals

Abstract

A study has been made of the electronic structures of the fluorides of silicon, phosphorus, sulphur, and chlorine by the VESCF molecular-orbital method with a minimal basis set, not including 3d-orbitals on the central atom. It proves possible to understand variations in bond lengths and charges on fluorine ligands, dipole moments, force constants, and some n.q.r. data. The calculations are found to be sensitive to assumptions about scaling factors for monocentric coulomb repulsion integrals and penetration integrals. We have not discovered any justification for including 3d-orbitals in the description of the electronic structure of these molecules.