Potential energy curves for $P_{2}$ and $P_{2}^{+}$ constructed from a strictly N-representable natural orbital functional Universiteit Antwerpen
The potential energy curves of P-2 and P-2(+) have been calculated using an approximate, albeit strictly N-representable, energy functional of the one-particle reduced density matrix: PNOF5. Quite satisfactory accord is found for the equilibrium bond lengths and dissociation energies for both species. The predicted vertical ionisation energy for P2 by means of the extended Koopmans' theorem is 10.57 eV, in good agreement with the experimental ...