Comment on the formation of He2− 4Ig states

The state He2− 4Ig (1σg2 1σu 1δg 1φu) of Adamowicz and Pluta [Chem. Phys. Lett. 179 (1991) 517] is shown to be (1σg2 1σu 2δg 1φu). A variational calculation using one electron diatomic molecular orbitals, as well as a complete active space self-consistent field calculation, predict it to be unbound with respect to its neutral parent states. It is argued that He2− 4Ig (1σg2 1σu 1δg 1φu) cannot exist.