Natural Expansion of Exact Wavefunctions. II. The Hydrogen-Molecule Ground State

Abstract

The Kolos and Roothaan wavefunction for H₂ has been analyzed into natural orbitals. It was found that the first natural orbital is nearly the SCF function. The first four natural orbitals provide a good description of the molecule and give a total energy of —1.169884 hartrees. Beyond the first four terms, the natural expansion becomes more slowly convergent.