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We have calculated the frequency-dependent exact exchange (EXX) kernel of time-dependent (TD) density functional theory employing our recently proposed computational method based on cubic splines. With this kernel we have calculated the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Maria Hellgren , Ulf von Barth

An exchange energy functional is proposed and tested for obtaining a class of excited-state energies using density-functional formalism. The functional is the excited-state counterpart of the local-density approximation functional for the…

Other Condensed Matter · Physics 2007-05-23 Prasanjit Samal , Manoj K. Harbola

Semi-local density functionals for the exchange-correlation energy of electrons are extensively used as it produce realistic and accurate results for finite and extended systems. The choice of techniques play crucial role in constructing…

Materials Science · Physics 2017-11-01 Subrata Jana , Prasanjit Samal

The exact interaction energy of a many-electron system is determined by the electron pair density, which is not well-approximated in standard Kohn-Sham density functional models. Here we study the (complicated but well-defined) exact…

Chemical Physics · Physics 2015-08-07 Huajie Chen , Gero Friesecke

Finding accurate exchange-correlation (XC) functionals remains the defining challenge in density functional theory (DFT). Despite 40 years of active development, the desired chemical accuracy is still elusive with existing functionals. We…

Chemical Physics · Physics 2024-09-11 Bikash Kanungo , Jeffrey Hatch , Paul M. Zimmerman , Vikram Gavini

In the description of the interaction between electrons beyond the classical Hartree picture, bare exchange often yields a leading contribution. Here we discuss its effect on optical spectra of solids, comparing three different frameworks:…

Other Condensed Matter · Physics 2009-11-11 Fabien Bruneval , Francesco Sottile , Valerio Olevano , Lucia Reining

Warm dense matter (WDM) has emerged as one of the frontiers of both experimental and theoretical physics and is challenging traditional concepts of plasma, atomic, and condensed-matter physics. While it has become common practice to model…

Plasma Physics · Physics 2021-10-01 Zhandos Moldabekov , Tobias Dornheim , Maximilian Böhme , Jan Vorberger , Attila Cangi

Modern density functional theory (DFT) calculations employ the Kohn-Sham (KS) system of non-interacting electrons as a reference, with all complications buried in the exchange-correlation energy (Exc). The adiabatic connection formula gives…

Other Condensed Matter · Physics 2009-10-02 Zhenfei Liu , Kieron Burke

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

Exact density functionals for the exchange and correlation energies are approximated in practical calculations for the ground-state electronic structure of a many-electron system. An important exact constraint for the construction of…

An interesting fundamental problem in density-functional theory of electronic structure of matter is to construct the exact Kohn-Sham (KS) potential for a given density. The exact potential can then be used to assess the accuracy of…

Atomic and Molecular Clusters · Physics 2019-05-22 Ashish Kumar , Rabeet Singh , Manoj K. Harbola

The Airy gas model of the edge electron gas is used to construct an exchange-energy functional which is an alternative to those obtained in the local density and generalized gradient approximations. Test calculations for rare gas atoms,…

Materials Science · Physics 2009-10-31 L. Vitos , B. Johansson , J. Kollár , H. L. Skriver

We calculate the imaginary part of the frequency-dependent dielectric function of bulk silicon by applying time-dependent density-functional theory based on the exact-exchange (EXX) Kohn-Sham (KS) band structure and the adiabatic…

Materials Science · Physics 2016-01-01 Yong-Hoon Kim , Martin Staedele , Andreas Goerling

Applying the novel exact-exchange (EXX) Kohn-Sham method within time-dependent density-functional theory, we obtained the optical absorption spectrum of bulk silicon in good agreement with experiments including excitonic features. Analysis…

Materials Science · Physics 2016-01-01 Yong-Hoon Kim , Andreas Goerling

We use the exact strong-interaction limit of the Hohenberg-Kohn energy density functional to approximate the exchange-correlation energy of the restricted Kohn-Sham scheme. Our approximation corresponds to a highly non-local density…

Strongly Correlated Electrons · Physics 2012-12-12 Francesc Malet , Paola Gori-Giorgi

The bandstructure of the zinc-blende phase of AlN, GaN, InN is calculated employing the exact-exchange (EXX) Kohn-Sham density-functional theory and a pseudopotential plane-wave approach. The cation semicore d electrons are treated both as…

Materials Science · Physics 2007-05-23 A. Qteish , A. I. Al-Sharif , M. Fuchs , M. Scheffler , S. Boeck , J. Neugebauer

The electronic band structures of two-dimensional materials are significantly different from those of their bulk counterparts, due to quantum confinement and strong modifications of electronic screening. An accurate determination of…

Mesoscale and Nanoscale Physics · Physics 2020-07-08 Tomáš Rauch , Miguel A. L. Marques , Silvana Botti

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

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

Following Hollins et al. [J. Phys.: Condens. Matter 29, 04LT01 (2017)], we invert the electronic ground state densities for various semiconducting and insulating solids calculated using several density functional approximations within the…

Chemical Physics · Physics 2025-11-05 Visagan Ravindran , Nikitas I. Gidopoulos , Stewart J. Clark