EVIDENCE FOR A METASTABLE STATE OF THE FUNDAMENTAL DIANION H2-

A resonance state with three equivalent electrons and one proton has b een identified. Large-scale calculations have been performed using the complex-rotation technique, and the results indicate that the investi gated S-4 degrees State of H2- is strongly correlated. The findings ar e rationalized by comparing with bound doubly charged anions, isoelect ronic states of the Li atom, and calculations in the infinite-dimensio n limit. In addition, the emerging picture is sustained by an analysis of the complex-rotated wave function.