From the graph, we see that only E + has a minimum corresponding to a separation of 1.3 Å and a total energy E + = − − 15.4 eV , which is less than the initial energy of the system, − − 13.6 eV . Thus, only the gerade state stabilizes the ion with a binding energy of 1.8 eV . As a result, the ground state of H 2 + is X 2 Σ Σ g + and this state ( | + ⟩ ) is called a bonding molecular orbital.