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A decomposition of the exact exchange-correlation potential of time-dependent density functional theory into an interaction component and a kinetic component offers a new starting point for non- adiabatic approximations. The components are…

Chemical Physics · Physics 2018-11-14 Johanna I. Fuks , Lionel Lacombe , Soeren E. B. Nielsen , Neepa T. Maitra

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 exchange-correlation energy in Kohn-Sham density functional theory is expressed as a functional of the electronic density and the Kohn-Sham orbitals. An alternative to Kohn-Sham theory is to express the energy as a functional of the…

Computational Physics · Physics 2009-10-31 S. Goedecker , C. Umrigar

From a simplified version of the mathematical structure of the strong coupling limit of the exact exchange-correlation functional, we construct an approximation for the electronic repulsion energy at physical coupling strength, which is…

Chemical Physics · Physics 2017-05-11 Stefan Vuckovic , Paola Gori-Giorgi

Standard approximations for the exchange-correlation functional are known to deviate from linear dependence of the energy on the electron and spin numbers (in -space). Violation of this flat-plane condition underlies the failure of all…

Classical Physics · Physics 2013-10-28 Ali M. Malek , Robert Balawender

Using time-dependent current-density functional theory, we derive analytically the dynamical exchange-correlation correction to the DC conductance of nanoscale junctions. The correction pertains to the conductance calculated in the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Na Sai , Michael Zwolak , Giovanni Vignale , Massimiliano Di Ventra

We derive a time-dependent density functional theory appropriate for calculating the near-edge X-ray absorption spectrum in molecules and condensed matter. The basic assumption is to increase the space of many-body wave functions from one…

Strongly Correlated Electrons · Physics 2015-06-16 G. F. Bertsch , A. Lee

Self-interaction is a fundamental flaw of practical Kohn-Sham Density Functional Theory (KS DFT) approximations responsible for numerous qualitative and even catastrophic shortcomings. Whereas self-interaction is easy to characterize in…

Chemical Physics · Physics 2024-07-16 Samuel A. Slattery , Edward F. Valeev

Improving the predictive capability of molecular properties in ab initio simulations is essential for advanced material discovery. Despite recent progress making use of machine learning, utilizing deep neural networks to improve quantum…

Chemical Physics · Physics 2021-09-22 Muhammad F. Kasim , Sam M. Vinko

We present an approach based on density-functional theory for the calculation of fundamental gaps of both finite and periodic two-dimensional (2D) electronic systems. The computational cost of our approach is comparable to that of total…

Materials Science · Physics 2021-08-11 Alberto Guandalini , Alice Ruini , Esa Räsänen , Carlo Andrea Rozzi , Stefano Pittalis

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

The predominance of Kohn-Sham density functional theory (KS-DFT) for the theoretical treatment of large experimentally relevant systems in molecular chemistry and materials science relies primarily on the existence of efficient software…

Computational Physics · Physics 2020-07-08 David B. Williams-Young , Wibe A. de Jong , Hubertus J. J. van Dam , Chao Yang

Energy gaps are crucial aspects of the electronic structure of finite and extended systems. Whereas much is known about how to define and calculate charge gaps in density-functional theory (DFT), and about the relation between these gaps…

Materials Science · Physics 2015-05-14 K. Capelle , G. Vignale , C. A. Ullrich

Density Functional Theory (DFT) underpins much of modern computational chemistry and materials science. Yet, the reliability of DFT-derived predictions of experimentally measurable properties remains fundamentally limited by the need to…

Using the Kohn-Sham (KS) inversion method of Hollins et al. [J. Phys.: Condens. Matter 29, 04LT01 (2017)], we invert densities from variational and diffusion quantum Monte Carlo (QMC) calculations to obtain benchmark QMC-KS potentials for a…

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 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

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

A self-consistent calculation scheme for correlated electron systems is created based on the density-functional theory (DFT). Our scheme is a multi-reference DFT (MR-DFT) calculation in which the electron charge density is reproduced by an…

Strongly Correlated Electrons · Physics 2009-11-13 Koichi Kusakabe , Naoshi Suzuki , Shusuke Yamanaka , Kizashi Yamaguchi

To extend the applicability of density functional theory for superconductors (SCDFT) to systems with significant particle-hole asymmetry, we construct a new exchange-correlation kernel entering the gap equation. We show that the kernel is…

Superconductivity · Physics 2013-07-22 Ryosuke Akashi , Ryotaro Arita