Potential energy curves for P2 and P2+ constructed from a strictly N-representable natural orbital functional

TL;DR

This paper calculates potential energy curves for P2 and P2+ using a strictly N-representable natural orbital functional, achieving good agreement with experimental data for bond lengths, energies, and vibrational properties.

Contribution

It introduces the use of the PNOF5 functional for accurate potential energy curves of P2 and P2+ with validation against experimental results.

Findings

Accurate equilibrium bond lengths and dissociation energies

Vertical ionization energy of 10.57 eV for P2 matching experiments

Vibrational energies and anharmonicities agree with experimental data

Abstract

The potential energy curves of P2 and P2+ 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 ionization energy for P2 by means of the extended Koopmans' theorem is 10.57 eV in good agreement with the experimental data. Comparison of the vibrational energies and anharmonicities with their corresponding experimental values supports the quality of the resultant potential energy curves.