Quartet states of He-2(+)

The low lying quartet spectrum of the molecular helium cation is investigat ed by configuration interaction calculations. Using large Gaussian basis se ts, potential energy curves for n(4)Sigma(u,g)(+) and n(4)II(u,g) are compu ted for the states n = 1,...,5. Several of these states lead to equilibrium configurations having rather extended bond lengths and some of them also a relatively large dissociation energy. The spectroscopic properties of thes e equilibrium configurations are studied. Quartet He-2(+) is most strongly bound in its lowest state 1(4)Sigma(u) with R-e = 3.424 Angstrom and D-e = 1.348 eV.