On the α and β parameters in Hückel theory including overlap for simple σ molecular systems

Ordinary LCAO-MO theory allows for the ab-initio definition of α and β parameters occurring in the Hückel theory including overlap of simple σ homonuclear systems. One- and two-electron terms not included in Hückel theory are explicitly considered. When such correction terms are neglected in the very spirit of Hückel theory, simple calculation in the hydrogenic approximation for the ground states of H2+, H2, He2+, He2 at the corresponding bond lengths shows semiquantitative agreement with experimental or accurate theoretical results for the bond energies, providing a simple and clear physical picture of the nature of the chemical bond.