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We propose a new approach to approximate the exchange and correlation (XC) functional in density functional theory. The XC potential is considered as an electrostatic potential, generated by a fictitious XC density, which is in turn a…

Chemical Physics · Physics 2013-05-29 Xavier Andrade , Alán Aspuru-Guzik

Using an end-to-end differentiable implementation of the Kohn-Sham self-consistent field equations, we obtain an accurate neural network-based exchange and correlation (XC) functional of the electronic density. The functional is optimized…

Chemical Physics · Physics 2021-06-09 Sebastian Dick , Marivi Fernandez-Serra

The reliability of density-functional calculations hinges on accurately approximating the unknown exchange-correlation (xc) potential. Common (semi-)local xc approximations lack the jump experienced by the exact xc potential as the number…

Atomic Physics · Physics 2021-01-15 M. J. P. Hodgson , E. Kraisler , E. K. U. Gross

The fundamental gap of an interacting many-electron system is given by the sum of the single-particle Kohn-Sham gap and the derivative discontinuity. The latter can be generated by advanced approximations to the exchange-correlation (XC)…

Strongly Correlated Electrons · Physics 2018-07-16 Maria Hellgren

A method for calculating the Kohn--Sham exchange-correlation potential, $v_\text{XC}(\mathbf{r})$, from a given electronic wavefunction is devised and implemented. It requires on input one- and two-electron density matrices and involves…

Chemical Physics · Physics 2015-08-19 Ilya G. Ryabinkin , Sviataslau V. Kohut , Viktor N. Staroverov

As part of a project to obtain better optical response functions for nano materials and other systems with strong excitonic effects we here calculate the exchange-correlation (XC) potential of density-functional theory (DFT) at a level of…

Other Condensed Matter · Physics 2009-11-13 M. Hellgren , U. von Barth

We present a new density-functional method of the self-consistent electronic-structure calculation which does not exploit any local density approximations (LDA). We use the exchange-correlation energy which consists of the exact exchange…

Statistical Mechanics · Physics 2009-10-30 Takao Kotani

Accurate exchange-correlation (XC) potentials for 3-dimensional systems -- via solution of the \emph{inverse} density functional theory (DFT) problem -- are now available to test the quality of DFT approximations. Herein, the \emph{exact}…

Chemical Physics · Physics 2021-11-18 Bikash Kanungo , Paul M. Zimmerman , Vikram Gavini

Most approximate exchange-correlation functionals used within density functional theory are constructed as the sum of two distinct contributions for exchange and correlation. Separating the exchange component from the entire functional is…

Condensed Matter · Physics 2009-10-28 Claudia Filippi , C. J. Umrigar , Xavier Gonze

We describe a method for calculating the exchange and correlation (XC) contributions to the total energy, effective potential, and stress tensor in the generalized gradient approximation. We avoid using the analytical expressions for the…

Materials Science · Physics 2009-11-07 L. C. Balbas , Jose Luis Martins , Jose M. Soler

Exchange-correlation potentials vxc and energy densities exc are derived for integer and fractional electron counts using an orbital-averaged Kohn-Sham inversion procedure. The reference densities for inversion come from full configuration…

Chemical Physics · Physics 2025-04-30 Vaibhav Khanna , Bikash Kanungo , Jeffrey Hatch , Joshua Kammeraad , Paul M. Zimmerman

In this work we have studied a new functional for the correlation energy obtained from the exact-exchange (EXX) approximation within time-dependent density functional theory (TDDFT). Correlation energies have been calculated for a number of…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Maria Hellgren , Ulf von Barth

The electronic exchange-correlation (XC) kernel constitutes a fundamental input for the estimation of a gamut of material properties such as the dielectric characteristics, the thermal and electrical conductivity, or the response to an…

Computational Physics · Physics 2024-02-26 Zhandos A. Moldabekov , Maximilian Böhme , Jan Vorberger , David Blaschke , Tobias Dornheim

An exchange-correlation energy functional $ E_{\mathrm xc} $ and the resultant exchange-correlation potential $ v_{\mathrm xc}({\bf r}) $ in density-functional theory are proposed using orbital-dependent coupling-constant-averaged pair…

Strongly Correlated Electrons · Physics 2007-05-23 Hiroshi Yasuhara , Masahiko Higuchi , Yoshiyuki Kawazoe

Popular approximations to the exchange-correlation (xc) energy of density functional theory do not yield the spatial `step' structures in the exact xc potential which are necessary to describe dissociation and electron excitation with the…

Materials Science · Physics 2021-09-08 M. J. P. Hodgson

We consider electronic exchange and correlation effects in density-functional calculations of two-dimensional systems. Starting from wave function calculations of total energies and electron densities of inhomogeneous model systems, we…

Mesoscale and Nanoscale Physics · Physics 2012-05-30 Ilja Makkonen , Mikko M. Ervasti , Ville Kauppila , Ari Harju

Knowledge of exact properties of the exchange-correlation (xc) functional is important for improving the approximations made within density functional theory. Features such as steps in the exact xc potential are known to be necessary for…

Strongly Correlated Electrons · Physics 2021-01-15 M. J. P. Hodgson , J. D. Ramsden , R. W. Godby

The exact exchange-correlation (XC) potential in time-dependent density-functional theory (TDDFT) is known to develop steps and discontinuities upon change of the particle number in spatially confined regions or isolated subsystems. We…

Mesoscale and Nanoscale Physics · Physics 2019-03-27 Daniel Vieira , K. Capelle , C. A. Ullrich

The exact static and time-dependent Kohn-Sham (KS) exchange-correlation (xc) potential is extremely challenging to approximate as it is a local multiplicative potential that depends on the electron density everywhere in the system. The KS…

Strongly Correlated Electrons · Physics 2021-01-15 M. J. P. Hodgson , J. Wetherell

The derivative discontinuity of the exchange-correlation functional of density-functional theory is cast as the difference of two types of electron affinities. We show that standard Kohn-Sham calculations can be used to calculate both…

Chemical Physics · Physics 2007-12-13 F. P. Rosselli , A. B. F. da Silva , K. Capelle
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