Outstanding Improvement in Removing the Delocalization Error by Global Natural Orbital Functional

TL;DR

This paper demonstrates that the global natural orbital functional (GNOF) significantly reduces charge delocalization errors, providing accurate energies and stable ionization potentials for complex systems, outperforming previous methods like PNOF7.

Contribution

The study introduces and evaluates GNOF, a new functional that effectively minimizes delocalization errors and balances static and dynamic correlation in electronic structure calculations.

Findings

GNOF practically eliminates charge delocalization error in many systems.

GNOF maintains stable ionization potentials with increasing system size.

GNOF outperforms previous functionals like PNOF7 in accuracy.

Abstract

This work assesses the performance of the recently proposed global natural orbital functional (GNOF) against the charge delocalization error. GNOF provides a good balance between static and dynamic electronic correlation leading to accurate total energies while preserving spin, even for systems with a highly multi-configurational character. Several analyses were applied to the functional, namely i) how the charge is distributed in super-systems of two fragments, ii) the stability of ionization potentials while increasing the system size, and iii) potential energy curves of a neutral and charged diatomic system. GNOF was found to practically eliminate the charge delocalization error in many of the studied systems or greatly improves the results obtained previously with PNOF7.