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In approximate Kohn-Sham density-functional theory, self-interaction manifests itself as the dependence of the energy of an orbital on its fractional occupation. This unphysical behavior translates into qualitative and quantitative errors…

Materials Science · Physics 2010-09-28 Ismaila Dabo , Andrea Ferretti , Nicolas Poilvert , Yanli Li , Nicola Marzari , Matteo Cococcioni

We propose approximations which go beyond the local density approximation for the short-range exchange and correlation density functionals appearing in a multi-determinantal extension of the Kohn-Sham scheme. A first approximation consists…

Chemical Physics · Physics 2009-11-10 Julien Toulouse , Francois Colonna , Andreas Savin

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 consider density functionals for exchange and correlation energies in two-dimensional systems. The functionals are constructed by making use of exact constraints for the angular averages of the corresponding exchange and correlation…

Strongly Correlated Electrons · Physics 2010-02-25 E. Rasanen , S. Pittalis

In the context of the density functional theory we consider the single particle excitation spectra of electron systems. As a result, we have related the single particle excitations with the eigenvalues of the corresponding Kohn-Sham…

Condensed Matter · Physics 2009-10-31 M. Ya. Amusia , V. R. Shaginyan

A functional $E_{xc}[\rho(\r,\epsilon)]$ is presented, in which the exchange and correlation energy of an electron gas depends on the local density of occupied states. A simple local parametrization scheme is proposed, entirely from first…

Materials Science · Physics 2009-11-10 Jose M. Soler

The exchange-correlation energy in Kohn-Sham density functional theory can be expressed exactly in terms of the change in the expectation of the electron-electron repulsion operator when, in the many-electron hamiltonian, this same operator…

Strongly Correlated Electrons · Physics 2009-08-05 Paola Gori-Giorgi , Giovanni Vignale , Michael Seidl

The self consistent version of the density functional theory is presented, which allows to calculate the ground state and dynamic properties of finite multi-electron systems. An exact functional equation for the effective interaction, from…

Materials Science · Physics 2017-08-23 M. Ya. Amusia , A. Z. Msezane , V. R. Shaginyan

Coulomb interactions that occur in electronic structure calculations are correlated by allowing basis function components of the interacting densities to polarize, thereby reducing the magnitude of the interaction. Exchange integrals of…

Chemical Physics · Physics 2022-05-16 Jerry L. Whitten

We present an alternative to the Kohn-Sham formulation of density functional theory for the ground-state properties of strongly interacting electronic systems. The idea is to start from the limit of zero kinetic energy and systematically…

Strongly Correlated Electrons · Physics 2015-05-13 Paola Gori-Giorgi , Michael Seidl , G. Vignale

Density functional approximations to the exchange-correlation energy of Kohn-Sham theory, such as the local density approximation and generalized gradient approximations, lack the well-known integer discontinuity, a feature that is critical…

Chemical Physics · Physics 2015-06-18 Martin A. Mosquera , Adam Wasserman

We present a practical and accurate density functional for the exchange-correlation energy of electrons in two dimensions. The exchange part is based on a recent two-dimensional generalized-gradient approximation derived by considering the…

Strongly Correlated Electrons · Physics 2010-06-30 E. Rasanen , S. Pittalis , J. G. Vilhena , M. A. L. Marques

By propagating the many-body Schr\"odinger equation, we determine the exact time-dependent Kohn-Sham potential for a system of strongly correlated electrons which undergo field-induced tunneling. Numerous features are entirely absent from…

Strongly Correlated Electrons · Physics 2021-01-15 Matthew J. P. Hodgson , James D. Ramsden , Jacob B. J. Chapman , Piers Lillystone , Rex W Godby

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

Ground and excited states of a confined negative Hydrogen ion has been pursued under Kohn-Sham density functional approach by invoking a physically motivated work-function-based exchange potential. The exchange-only results are of near…

Atomic Physics · Physics 2022-05-23 Sangita Majumdar , Neetik Mukherjee , Amlan K. Roy

We train a neural network as the universal exchange-correlation functional of density-functional theory that simultaneously reproduces both the exact exchange-correlation energy and potential. This functional is extremely non-local, but…

Computational Physics · Physics 2019-10-10 Jonathan Schmidt , Carlos L. Benavides-Riveros , Miguel A. L. Marques

The correlation energy in density functional theory can be expressed exactly in terms of the change in the probability of finding two electrons at a given distance $r_{12}$ (intracule density) when the electron-electron interaction is…

Other Condensed Matter · Physics 2017-08-23 Paola Gori-Giorgi , Michael Seidl , Andreas Savin

While in principle exact, Kohn-Sham density functional theory -- the workhorse of computational chemistry -- must rely on approximations for the exchange-correlation functional. Despite staggering successes, present-day approximations still…

We present and discuss some ideas concerning an ``average-pair-density functional theory'', in which the ground-state energy of a many-electron system is rewritten as a functional of the spherically and system-averaged pair density. These…

Materials Science · Physics 2009-11-11 Paola Gori-Giorgi , Andreas Savin

Most treatments of electron-electron correlations in dense plasmas either ignore them entirely (random phase approximation) or neglect the role of ions (jellium approximation). In this work, we go beyond both these approximations to derive…

Plasma Physics · Physics 2020-02-05 Nathaniel R. Shaffer , Charles E. Starrett