Study of the Electronic Ground State of the Ammonia Molecule

Abstract

The electronic structure of the ground state of the ammonia molecule has been calculated in the SCF LCAO MO approximation for two sets of internuclear separations: the experimentally observed values and a symmetric planar arrangement. The effect of limited configuration interaction on these results has also been investigated. The atomic orbitals used include 1s, 2s, and 2p nitrogen orbitals and 1s hydrogen orbitals, the nitrogen orbitals being the Hartree and Hartree solutions of the Hartree‐Fock problem for the neutral nitrogen atom and the hydrogen orbitals being the standard free atom functions. All integrals were calculated using the method of Barnett and Coulson and Lundqvist and Löwdin, the only approximation involved being the mathematical one of terminating infinite series. The significance of the results is discussed, and calculations of the binding energy, the dipole moment, and other molecular properties are compared with experiment.