Using a form of double perturbation theory we present results of calculations on the ground state energies for the diatomic systems H2+, HHe2+, H2 and HHe+. For the homonuclear systems the energy values are unexpectedly good. For the heteronuclear cases the results are very encouraging and lead to optimism about the application of the method to larger systems which contain one heavy atom.
Bibliographical noteFunding Information:
One of us (K. B. L.) would like to acknowledge the support of the Science Research Council. We would also like to acknowledge the support of the U.S. Army through its European Research Office.