Density-Corrected Density Functional Theory for Molecular Properties

Abstract

Density-corrected (DC) density functional theory (DFT) has been proposed to overcome difficulties related to the self-interaction error. The procedure uses the Hartree−Fock electron density (matrix) non-self-consistently in conjunction with an approximate functional. DC-DFT has so far mainly been tested for total energy differences, whereas other types of molecular properties have not been evaluated systematically. This work focuses on the performance of DC-DFT for molecular properties, namely, dipole moments, static polarizabilities, and electric field gradients (EFGs) at atomic nuclei. Accurate reference data were generated from coupled-cluster theory to assess the performance of DC and self-consistent DFT calculations for twelve molecules, including diatomics with transition metals. DC-DFT does no harm in dipole moment calculations, but it negatively impacts the polarizability in at least one case. DC-DFT performs well for EFGs, even for the difficult case of CuCl.

Density-Corrected Density Functional Theory for Open Shells: How to Deal with Spin Contamination

“…HF-DFT not only works for the energetics but also provides sufficient accuracy similar to self-consistent DFT in various molecular properties. 18 On the other hand, the more nuanced DC(HF)-DFT only employs HF densities when density-driven errors are believed to be large. This more nuanced approach is vital in several important ways: (a) in finding significant improvements due to HF densities in large data sets, where the vast majority of the data does not have significant density-driven errors; 2 (b) in isolating improved parameters in empirical functional construction by fitting only to functional errors, not density-driven ones; 19 and (c) in improving the coefficients in empirical corrections to dispersion corrections, which can be corrupted when density-driven errors are large.…”

“…The cases where HF-DFT showed remarkable success include pure water and aqueous systems, − electron and hole polaron defects, crystal polymer conformational energies, making and breaking of internal hydrogen bonds, torsional barriers, electron affinity, dissociation energy curves of heteronuclear molecules, , radical ions in aqueous solution, spin gaps of Fe­(II) complexes, halogen and chalcogen binding energies, etc. HF-DFT not only works for the energetics but also provides sufficient accuracy similar to self-consistent DFT in various molecular properties …”