Nuclear repulsion effects in molecular bonding

Potential energy curves of a single electron moving in the joint Coulomb field of two fixed nuclei of equal arbitrary charge, Z, have been calculated exactly using a scaling relationship derived in an earlier paper. The resulting potential curves display some interesting features. For Z<1 the 2 pσ "antibonding" orbital becomes "bonding", while the 1 sσ potential well becomes deeper. For larger Z, the 1 sσ orbital eventually becomes "antibonding" but the potential curve passes through a number of distinct intermediate stages before a purely repulsive potential is reached.