Approximate Self-Consistent Molecular Orbital Theory. IV. Calculations on Molecules Including the Elements Sodium through Chlorine

The CNDO method is extended to molecules containing the elements sodium through chlorine and used to examine the importance of the 3d orbitals of these elements to molecular properties. An examination of the radial dependence of the 3d orbitals is carried out by performing parallel calculations with three different basis sets on a selection of molecules. A basis set in which the 3d orbitals are somewhat contracted is found to best predict molecular geometries, dipole moments, and bending force constants. The molecular dipole moments are found to present the most persuasive evidence for 3d participation, while most molecular geometries are relatively insensitive to inclusion of atomic orbitals of d symmetry.