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The time-dependent exchange-correlation potential has an unusual task in directing fictitious non-interacting electrons to move with exactly the same probability density as true interacting electrons. This has intriguing implications for…

Chemical Physics · Physics 2024-06-19 Davood Dar , Lionel Lacombe , Neepa T. Maitra

Time-dependent (TD) density functional theory (TDDFT) promises a numerically tractable account of many-body electron dynamics provided good simple approximations are developed for the exchange-correlation (XC) potential functional (XCPF).…

Other Condensed Matter · Physics 2008-08-29 Roi Baer

A diagrammatic expansion for the dynamic exchange-correlation kernel f_xc of time dependent density functional theory is formulated. It is shown that f_xc has no singularities at Kohn-Sham transition energies in every order of the…

Condensed Matter · Physics 2009-11-07 I. V. Tokatly , R. Stubner , O. Pankratov

Density functional theory (DFT) and linear-response time-dependent density functional theory (LR-TDDFT) rely on an exchange-correlation (xc) approximation that provides not only energy but also its functional derivatives that enter the…

Chemical Physics · Physics 2026-04-08 Xiaoyu Zhang

Over the past few years it has been pointed out that direct inversion of accurate but approximate ground state densities leads to Kohn-Sham exchange-correlation (xc) potentials that can differ significantly from the exact xc potential of a…

Atomic Physics · Physics 2020-08-26 Ashish Kumar , Rabeet Singh , Manoj K. Harbola

Realizing the potential for predictive density functional calculations of matter under extreme conditions depends crucially upon having an exchange-correlation (XC) free energy functional accurate over a wide range of state conditions.…

Materials Science · Physics 2018-02-21 Valentin V. Karasiev , James W. Dufty , S. B. Trickey

Capturing the discontinuous shift by $\Delta$ in the exact exchange-correlation (xc) potential is the standard proposal for calculating the fundamental gap, $E_\mathrm{g}$, from the Kohn-Sham (KS) gap, $\varepsilon_\mathrm{g}$, within KS…

Materials Science · Physics 2021-01-14 M. J. P. Hodgson , J. Wetherell , Emmanuel Fromager

We consider an analytically solvable model of two interacting electrons that allows for the calculation of the exact exchange-correlation kernel of time-dependent density functional theory. This kernel, as well as the corresponding density…

Strongly Correlated Electrons · Physics 2017-05-04 Luis Cort , Daniel Karlsson , Giovanna Lani , Robert van Leeuwen

We analyze possible nonlinear exciton-exciton correlation effects in the optical response of semiconductors by using a time-dependent density-functional theory (TDDFT) approach. For this purpose, we derive the nonlinear (third-order) TDDFT…

Materials Science · Physics 2015-06-16 Volodymyr Turkowski , Michael N. Leuenberger

We present an exact decomposition of the complete wavefunction for a system of nuclei and electrons evolving in a time-dependent external potential. We derive formally exact equations for the nuclear and electronic wavefunctions that lead…

Other Condensed Matter · Physics 2015-05-19 Ali Abedi , Neepa T. Maitra , E. K. U. Gross

We formulate diagrammatic rules for many-body perturbation theory which uses Kohn-Sham (KS) Green's functions as basic propagators. The diagram technique allows to study the properties of the dynamic nonlocal exchange-correlation (xc)…

Condensed Matter · Physics 2009-10-31 I. V. Tokatly , O. Pankratov

The dynamical, long-wavelength longitudinal and transverse exchange-correlation potentials for a homogeneous electron gas are evaluated in a microscopic model based on an approximate decoupling of the equation of motion for the…

Condensed Matter · Physics 2009-10-30 S. Conti , R. Nifosi' , M P Tosi

We have calculated the correlation energy of the homogeneous electron gas (HEG) and the dissociation energy curves of molecules with covalent bonds from a novel implementation of the adiabatic connection fluctuation dissipation (ACFD)…

Strongly Correlated Electrons · Physics 2015-06-22 Nicola Colonna , Maria Hellgren , Stefano de Gironcoli

We present results of a photon-free exchange-correlation functional within the local density approximation (pxcLDA) for quantum electrodynamics density functional theory (QEDFT) that efficiently describes the electron density of…

Measurable spectra are theoretically very often derived from complicated many-body Green's functions. In this way, one calculates much more information than actually needed. Here we present an in principle exact approach to construct…

Materials Science · Physics 2010-09-08 Matteo Gatti , Valerio Olevano , Lucia Reining , Ilya V. Tokatly

We present here a formalism based on time-dependent density-functional theory (TDDFT) to describe characteristics of both intra- and inter-valley excitons in semiconductors, the latter of which had remained a challenge. Through the usage of…

Materials Science · Physics 2023-05-10 Jia Shi , Volodymyr Turkowski , Duy Le , Talat S. Rahman

Recent progress has been made in capturing spectral features of electronic states of double-excitation character in time-dependent density functional theory (TDDFT) through a frequency-dependent kernel. While it might appear that this…

Chemical Physics · Physics 2026-05-04 Dhyey Ray , Anna Baranova , Davood B. Dar , Neepa T. Maitra

We employ correlation-consistent effective core potentials (ccECPs) to perform exact or nearly exact correlation and total energy calculations for the fifth-row elements (Rb-Xe). Total energies are calculated using various correlated…

Materials Science · Physics 2025-12-22 Aqsa Shaikh , Omar Madany , Benjamin Kincaid , Lubos Mitas

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

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