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In comparison with the accurate data on the on-top electron density n(0) in the proton-embedded electron gas with the density parameter r_s in the range 1-12 obtained by diffusion Monte Carlo (DMC) simulations, we have successfully…

Materials Science · Physics 2018-07-18 Yasutami Takada

We use variational quantum Monte Carlo to calculate the density-functional exchange-correlation hole n_{xc}, the exchange-correlation energy density e_{xc}, and the total exchange-correlation energy E_{xc}, of several electron gas systems…

Materials Science · Physics 2009-10-31 Maziar Nekovee , W. M. C. Foulkes , R. J. Needs

The flexibility of common generalized gradient approximation for the exchange-correlation energy is investigated by monitoring the equilibrium volume of transition metals. It is shown that no universal gradient-level approximation yielding…

Materials Science · Physics 2015-06-05 H. Levämäki , L. Vitos , M. P. J. Punkkinen , K. Kokko

Using a linear combination of atomic orbitals approach, we report a systematic comparison of various Density Functional Theory (DFT) and hybrid exchange-correlation functionals for the prediction of the electronic and structural properties…

Materials Science · Physics 2008-05-07 D. I. Bilc , R. Orlando , R. Shaltaf , G. -M. Rignanese , Jorge Íñiguez , Ph. Ghosez

We present a detailed study of the exchange-correlation hole and exchange-correlation energy per particle in the Si crystal as calculated by the Variational Monte Carlo method and predicted by various density functional models. Nonlocal…

Materials Science · Physics 2009-11-07 A. C. Cancio , M. Y. Chou , Randolph Q. Hood

Implicit and explicit density functionals for the exchange energy in finite two-dimensional systems are developed following the approach of Becke and Roussel [Phys. Rev. A 39, 3761 (1989)]. Excellent agreement for the exchange-hole…

Strongly Correlated Electrons · Physics 2008-05-08 S. Pittalis , E. Rasanen , N. Helbig , E. K. U. Gross

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

Density functionals with a range-separated treatment of the exchange energy are known to improve upon their semilocal forerunners and fixed-fraction hybrids. The conversion of a given semilocal functional into its short-range analog is not…

Chemical Physics · Physics 2019-09-09 Dimitri N. Laikov

We show how one can construct \alert{a simple} exchange functional by extending the well-know local-density approximation (LDA) to finite uniform electron gases. This new generalized local-density approximation (GLDA) functional uses only…

Chemical Physics · Physics 2017-05-01 Pierre-François Loos

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

Approximations to the exact density functional for the exchange-correlation energy of a many-electron ground state can be constructed by satisfying constraints that are universal, i.e., valid for all electron densities. Gedanken densities…

Chemical Physics · Physics 2015-06-19 John P. Perdew , Adrienn Ruzsinszky , Jianwei Sun , Kieron Burke

We present a systematic study that clarifies validity and limitation of current hybrid functionals in density functional theory for structural and electronic properties of various semiconductors and insulators. The three hybrid functionals,…

Materials Science · Physics 2015-03-19 Yu-ichiro Matsushita , Kazuma Nakamura , Atsushi Oshiyama

We implement a Becke fuzzy cells type space partitioning scheme for the purposes of exchange-correlation within the GPAW projector augmented-wave method based density functional theory code. Space partitioning is needed in the situation…

Materials Science · Physics 2019-02-20 H. Levämäki , M. Kuisma , K. Kokko

We analyze the methodology and the performance of subsystem density functional theory (DFT) with meta-generalized gradient approximation (meta-GGA) exchange-correlation functionals for non-bonded systems. Meta-GGA functionals depend on the…

Other Condensed Matter · Physics 2015-05-05 S. Śmiga , E. Fabiano , S. Laricchia , L. A. Constantin , F. Della Sala

A self-consistent scheme for determining the optimal fraction of exact exchange for full-range hybrid functionals is presented and applied to the calculation of band gaps and dielectric constants of solids. The exchange-correlation…

Materials Science · Physics 2015-01-15 Jonathan H Skone , Marco Govoni , Giulia Galli

We study the core hole-electron correlation in coherently coupled molecules by energy dispersive near edge X-ray absorption fine-structure spectroscopy. In a transient phase, which exists during the transition between two bulk arrangements,…

Materials Science · Physics 2013-12-03 M. Scholz , F. Holch , C. Sauer , M. Wiessner , A. Schöll , F. Reinert

We present an ab initio study of core excitations of solid-state materials focussing on the role of electron-hole correlation. In the framework of an all-electron implementation of many-body perturbation theory into the exciting code, we…

Materials Science · Physics 2017-04-21 Christian Vorwerk , Caterina Cocchi , Claudia Draxl

Electron correlation in solid has a major impact on material properties. However, it has been studied mainly by theory, with very limited direct experimental investigations. Here, we report the results of real-space measurement of dynamic…

We model a Kohn-Sham potential with a discontinuity at integer particle numbers derived from the GLLB approximation of Gritsenko et al. We evaluate the Kohn-Sham gap and the discontinuity to obtain the quasiparticle gap. This allows us to…

Materials Science · Physics 2013-05-29 M. Kuisma , J. Ojanen , J. Enkovaara , T. T. Rantala

We propose a computationally simple model of Auger and APECS line shapes from open-band solids. Part of the intensity comes from the decay of unscreened core-holes and is obtained by the two-body Green's function $G^{(2)}_{\omega}$, as in…

Strongly Correlated Electrons · Physics 2009-10-31 A. Marini , M. Cini