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Quantum--Mechanical methods that are both computationally fast and accurate are not yet available for electronic excitations having charge transfer character. In this work, we present a significant step forward towards this goal for those…

Chemical Physics · Physics 2015-06-12 Michele Pavanello , Troy Van Voorhis , Lucas Visscher , Johannes Neugebauer

Using a Hartree-Fock mesh method and a configuration interaction approach based on a generalized Gaussian basis set we investigate the behaviour of the exchange and correlation energies of small atoms and molecules, namely th e helium and…

Atomic Physics · Physics 2009-10-31 P. Schmelcher , M. V. Ivanov , W. Becken

The density-constrained time-dependent Hartree-Fock (DC-TDHF) theory is a fully microscopic approach for calculating heavy-ion interaction potentials and fusion cross sections below and above the fusion barrier. We discuss recent…

Nuclear Theory · Physics 2014-02-07 A. S. Umar , V. E. Oberacker , R. Keser , J. A. Maruh , P. -G. Reinhard

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

HF-DFT, the practice of evaluating approximate density functionals on Hartree-Fock densities, has long been used in testing density functional approximations. Density-corrected DFT (DC-DFT) is a general theoretical framework for identifying…

Chemical Physics · Physics 2021-10-18 Suhwan Song , Stefan Vuckovic , Eunji Sim , Kieron Burke

Reliable calculations of the structure of heavy elements are crucial to address fundamental science questions such as the origin of the elements in the universe. Applications relevant for energy production, medicine, or national security…

It is shown that four-component (4C), quasi-four-component (Q4C), and exact two-component (X2C) relativistic Hartree-Fock (HF) equations can be implemented in an unified manner, by making use of the atomic nature of the small components of…

Chemical Physics · Physics 2023-11-28 Wenjian Liu

In density functional theory (DFT), exact constraints, fundamental mathematical properties of the exchange-correlation (XC) energy and its underlying XC hole, along with paradigm systems such as the uniform electron gas and the hydrogen…

Materials Science · Physics 2026-03-13 Yan Oueis , Akilan Ramasamy , James W. Furness , Jamin Kidd , Timo Lebeda , Jianwei Sun

The question of how density functional theory (DFT) compares with Hartree-Fock (HF) for the computation of momentum-space properties is addressed in relation to systems for which (near) exact Kohn-Sham (KS) and HF one-electron matrices are…

Atomic Physics · Physics 2007-05-23 Sebastien Ragot

We develop a statistical method to learn a molecular Hamiltonian matrix from a time-series of electron density matrices. We extend our previous method to larger molecular systems by incorporating physical properties to reduce…

Chemical Physics · Physics 2021-08-03 Prachi Gupta , Harish S. Bhat , Karnamohit Ranka , Christine M. Isborn

Linear scaling quantum chemical methods for Density Functional Theory are extended to the condensed phase at the $\Gamma$-point. For the two-electron Coulomb matrix, this is achieved with a tree-code algorithm for fast Coulomb summation [J.…

Materials Science · Physics 2009-11-10 C. J. Tymczak , Matt Challacombe

Density functional theory was used to study the nonmagnetic (NM) and ferromagnetic (FM) phases of face-centered cubic cerium. Functionals of four levels of approximations for the exchange-correlation energy were used: LDA, PBE, LDA/PBE+$U$,…

Strongly Correlated Electrons · Physics 2014-04-09 Fabien Tran , Ferenc Karsai , Peter Blaha

Exploratory variational pseudopotential density functional calculations are performed for the electronic properties of many-electron systems in the 3D cartesian coordinate grid (CCG). The atom-centered localized gaussian basis set,…

Chemical Physics · Physics 2015-05-18 Amlan K Roy

Density functional theory has been an essential analysis tool for both theoretical and experimental chemists since accurate hybrid functionals were developed. Here we propose a local hybrid method derived from the optimized effective…

Chemical Physics · Physics 2017-03-24 Jaewook Kim , Kwangwoo Hong , Sang-Yeon Hwang , Seongok Ryu , Sunghwan Choi , Woo Youn Kim

We introduce an energy functional for ground-state electronic structure calculations. Its variables are the natural spin-orbitals of singlet many-body wave functions and their joint occupation probabilities deriving from controlled…

Chemical Physics · Physics 2016-12-04 Ralph Gebauer , Morrel H. Cohen , Roberto Car

In this article, we discuss how a kind of hybrid computation, which employs symbolic, numeric, classic, and quantum algorithms, allows us to conduct Hartree-Fock electronic structure computation of molecules. In the proposed algorithm, we…

Quantum Physics · Physics 2024-06-19 Ichio Kikuchi , Akihito Kikuchi

We have developed and implemented a self-consistent density functional method using standard norm-conserving pseudopotentials and a flexible, numerical LCAO basis set, which includes multiple-zeta and polarization orbitals. Exchange and…

Multinucleon transfer processes in heavy-ion reactions at energies slightly above the Coulomb barrier are investigated in a fully microscopic framework of the time-dependent Hartree-Fock (TDHF) theory. Transfer probabilities are calculated…

Nuclear Theory · Physics 2016-05-25 Kazuyuki Sekizawa , Kazuhiro Yabana

The construction of the Hamiltonian matrix \textbf{H} is an essential, yet computationally expensive step in \textit{ab-initio} device simulations based on density-functional theory (DFT). In homogeneous structures, the fact that a unit…

Disordered Systems and Neural Networks · Physics 2026-02-03 Chen Hao Xia , Manasa Kaniselvan , Marko Mladenoivić , Mathieu Luisier

High-throughput DFT calculations are key to screening existing/novel materials, sampling potential energy surfaces, and generating quantum mechanical data for machine learning. By including a fraction of exact exchange (EXX), hybrid…