Combining density-based dynamical correlation with a reduced-density-matrix strong-correlation description
Year: 2020
Type: article
Abstract: A combined density and density-matrix functional method is proposed for the calculation of potential energy curves of molecular multibond dissociation. Its density-matrix part, a pair-density functional, efficiently approximates the ab initio pair density of the complete active space (CAS) method. The corresponding approximate on-top pair density $\mathrm{\ensuremath{\Pi}}$ is employed to correct for double counting in the correlation energy functional. The proposed $\mathrm{ELS}+$ method, which augments the extended L\"owdin-Shull (ELS) density-matrix functional with the $\mathrm{\ensuremath{\Pi}}$-based scaled density functional, closely reproduces potential curves of the paradigmatic multibond dissociation in ${\mathrm{N}}_{2}, {\mathrm{H}}_{2}\mathrm{O}$, and ${\mathrm{H}}_{2}\mathrm{CO}$ molecules calculated with the recently proposed $\mathrm{CAS}\mathrm{\ensuremath{\Pi}}\mathrm{DFT}$ [CAS augmented with the $\mathrm{\ensuremath{\Pi}}$-based scaled correlation correction of density functional theory (DFT)] method. Furthermore, with the additional correction for the intrafragment correlation between the broken-bond electrons, $\mathrm{ELS}++$ reproduces well the benchmark potential curve of the ${\mathrm{N}}_{2}$ molecule by Lie and Clementi.
Source: Physical Review A
Authors: Robert van Meer, Oleg Gritsenko, Jeng-Da Chai
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3039779986