1. Die Erhaltung der Orbitalsymmetrie
2. At large separation it is clear that the single configuration molecular orbital description is inadequate. The wave function c1 (S)2 + C2 (A)2 describes the molecule better, with c2-c1 as R ∞. At Re the (S)2 configuration predominates.
3. Some clear instances of configurational crossing have been described by E.F. Hayes and G.V. Pfeiffer, J. Amer. Chem. Soc., 90, 473 (1968).
4. Geometry of Ozone and Azide Ion in Ground and Certain Excited States
5. 49, 2473 (1968).