Reformulation of thermally assisted-occupation density functional theory in the Kohn-Sham framework.

Journal Article (Journal Article)

We reformulate the thermally assisted-occupation density functional theory (TAO-DFT) into the Kohn-Sham single-determinant framework and construct two new post-self-consistent field (post-SCF) static correlation correction schemes, named rTAO and rTAO-1. In contrast to the original TAO-DFT with the density in an ensemble form, in which each orbital density is weighted with a fractional occupation number, the ground-state density is given by a single-determinant wavefunction, a regular Kohn-Sham (KS) density, and total ground state energy is expressed in the normal KS form with a static correlation energy formulated in terms of the KS orbitals. In post-SCF calculations with rTAO functionals, an efficient energy scanning to quantitatively determine θ is also proposed. The rTAOs provide a promising method to simulate systems with strong static correlation as original TAO, but simpler and more efficient. We show that both rTAO and rTAO-1 is capable of reproducing most results from TAO-DFT without the additional functional Eθ used in TAO-DFT. Furthermore, our numerical results support that, without the functional Eθ , both rTAO and rTAO-1 can capture correct static correlation profiles in various systems.

Full Text

Duke Authors

Cited Authors

  • Yeh, S-H; Yang, W; Hsu, C-P

Published Date

  • May 2022

Published In

Volume / Issue

  • 156 / 17

Start / End Page

  • 174108 -

PubMed ID

  • 35525641

Electronic International Standard Serial Number (EISSN)

  • 1089-7690

International Standard Serial Number (ISSN)

  • 0021-9606

Digital Object Identifier (DOI)

  • 10.1063/5.0087012

Language

  • eng