Pauli forces and the valence shell electron pair repulsion model for water and ammonia

Abstract

It is shown that the two effects of antisymmetry (Pauli exclusion principle) within the correct SCF wavefunctions cannot bend linear H/sub 2/O or planar NH/sub 3/ without classical electronic coulombic repulsion (CER) between LMO charge clouds in the SCF energy expression. These two effects are the orthogonality of the molecular orbitals (MOs) and the electron-exchange interactions between the LMOs. This result is in direct contradiction to the presently accepted valence shell electron pair repulsion (VSEPR) model, which attributes the geometries of molecules to Pauli forces between localized electron pairs. It is argued that the Walsh MO energy correlation diagrams, based on the integral Hellmann-Feynman theorem, are a more correct simple model for molecular geometries.