Ionic Configuration Interaction in Some Excited States of the Hydrogen Molecule

Using the Rayleigh-Ritz variational method, the 1 σ states of the hydrogen molecule arising from the [H(1s), H(2s or p)], [H + , H - (1s) 2 ] and [H(1s), H(3s, p or d)] configurations are investigated in the region of transition from ionic to homopolar character. Potential energy curves are given for these regions. It is shown that the admixture of configurations has a very considerable effect on the potential energy curves even at large nuclear separations. The ionic content is defined and calculated for [H(1s), H(3s, p or d)] states and found to vary rapidly in the transition region. The bearing of this result on collision theory is discussed briefly.