Density functional theory in transition-metal chemistry: a self-consistent Hubbard U approach

TL;DR

This paper introduces a self-consistent Hubbard U correction within density functional theory to improve the description of transition-metal active sites, achieving better agreement with correlated-electron calculations.

Contribution

It presents a novel self-consistent linear-response method to determine the Hubbard U, enhancing DFT accuracy for transition-metal chemistry.

Findings

Accurately models energetics and structures of transition-metal complexes

Achieves excellent agreement with correlated-electron quantum chemistry

Applicable to various transition-metal reactions and systems

Abstract

Transition-metal centers are the active sites for many biological and inorganic chemical reactions. Notwithstanding this central importance, density-functional theory calculations based on generalized-gradient approximations often fail to describe energetics, multiplet structures, reaction barriers, and geometries around the active sites. We suggest here an alternative approach, derived from the Hubbard U correction to solid-state problems, that provides an excellent agreement with correlated-electron quantum chemistry calculations in test cases that range from the ground state of Fe$_2$ and Fe$_2^-$ to the addition-elimination of molecular hydrogen on FeO$^+$. The Hubbard U is determined with a novel self-consistent procedure based on a linear-response approach.