A GGA plus U approach to effective electronic correlations in thiolate-ligated iron-oxo (IV) porphyrin

Authors

Justin Elenewski, Virginia Commonwealth University
John C. Hackett, Virginia Commonwealth UniversityFollow

Document Type

Article

Original Publication Date

2012

Journal/Book/Conference Title

The Journal of Chemical Physics

Volume

137

DOI of Original Publication

10.1063/1.4755290

Comments

Originally published at https://doi.org/10.1063/1.4755290

Date of Submission

October 2015

Abstract

High-valent oxo-metal complexes exhibit correlated electronic behavior on dense, low-lying electronic state manifolds, presenting challenging systems for electronic structure methods. Among these species, the iron-oxo (IV) porphyrin denoted Compound I occupies a privileged position, serving a broad spectrum of catalytic roles. The most reactive members of this family bear a thiolate axial ligand, exhibiting high activity toward molecular oxygen activation and substrate oxidation. The default approach to such systems has entailed the use of hybrid density functionals or multi-configurational/multireference methods to treat electronic correlation. An alternative approach is presented based on the GGA+U approximation to density functional theory, in which a generalized gradient approximation (GGA) functional is supplemented with a localization correction to treat on-site correlation as inspired by the Hubbard model. The electronic structure of thiolate-ligated iron-oxo (IV) porphyrin and corresponding Coulomb repulsion U are determined both empirically and self-consistently, yielding spin-distributions, state level splittings, and electronic densities of states consistent with prior hybrid functional calculations. Comparison of this detailed electronic structure with model Hamiltonian calculations suggests that the localized 3d iron moments induce correlation in the surrounding electron gas, strengthening local moment formation. This behavior is analogous to strongly correlated electronic systems such as Mott insulators, in which the GGA+U scheme serves as an effective single-particle representation for the full, correlated many-body problem.

Rights

Elenewski, J. E., and Hackett, J. C. A GGA plus U approach to effective electronic correlations in thiolate-ligated iron-oxo (IV) porphyrin. The Journal of Chemical Physics, 137, 124311 (2012). Copyright © 2012 American Institute of Physics.

Is Part Of

VCU Medicinal Chemistry Publications