Self-Consistent Field Electron Distributions in Molecules with Second-Row Elements

Abstract

Electron density maps are obtained for PN, P₂, MgO, PO, PO⁻, PO₂⁻, SO, SiH₄, PH₃, and H₂S using SCF–LCAO–MO wavefunctions. Difference maps are employed to compare the molecular charge distributions with the constituent atomic densities. Quantitative dissimilarities are found to exist between near‐minimum basis set SCF and near‐Hartree–Fock total densities, but difference maps are similar provided the atomic wavefunctions employed are of the same accuracy as the molecular functions. Covalent and ionic charge distributions are contrasted; trends among the oxides and hydrides are noted. Addition of the heavy‐atom $\text{3d}$ orbitals to minimum basis sets increases the electron density in the bonding regions. The optimum size of the $\text{3d}$ orbitals is discussed.