Exact solution of the Hartree-Fock equation for the H2 molecule in the linear-combination-of-atomic-orbitals approximation -: art. no. 010501

It was shown that the conventional linear-combination-of-atomic-orbitals (LCAO) approximation does not preserve correlation properties of molecular orbitals and a total molecular wave function of the Hartree-Fock (HF) method in the limit of a united atom. On this basis the correct form of the LCAO approximation has been derived for a homonuclear molecule. The Hartree-Fock calculations of the H-2 molecule with the new form of the LCAO approximation have given the total energy with the highest numerical precision. Qualitative conclusions about chemical bonds in molecules are derived from an analysis of the exact solution of the HF equation.