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To understand sparse systems we must account for both strong local atom bonds and weak nonlocal van der Waals forces between atoms separated by empty space. A fully nonlocal functional form [H. Rydberg, B.I. Lundqvist, D.C. Langreth, and M.…

Materials Science · Physics 2009-11-10 H. Rydberg , M. Dion , N. Jacobson , E. Schroder , P. Hyldgaard , S. I. Simak , D. C. Langreth , B. I. Lundqvist

We generalize the recently developped "internal" Density Functional Theory (DFT) and Kohn-Sham scheme to multicomponent systems. We obtain a general formalism, applicable for the description of multicomponent self-bound systems (as…

Quantum Physics · Physics 2015-03-19 Jeremie Messud

Hybrid density functionals replace a fraction of an underlying generalized-gradient approximation (GGA) exchange description with a Fock-exchange component. Range-separated hybrids (RSHs) also effectively screen the Fock-exchange component…

Materials Science · Physics 2022-01-05 Vivekanand Shukla , Yang Jiao , Carl Frostenson , Per Hyldgaard

The ground state electron density -- obtainable using Kohn-Sham Density Functional Theory (KS-DFT) simulations -- contains a wealth of material information, making its prediction via machine learning (ML) models attractive. However, the…

We introduce an individually fitted screened-exchange interaction for the time-dependent Hartree-Fock (TDHF) method and show that it resolves the missing binding energies in polymethine organic dye molecules compared to time-dependent…

Chemical Physics · Physics 2024-06-21 Nadine C. Bradbury , Barry Y. Li , Tucker Allen , Justin R. Caram , Daniel Neuhauser

We present a novel algorithm, named the 2D-FFAST, to compute a sparse 2D-Discrete Fourier Transform (2D-DFT) featuring both low sample complexity and low computational complexity. The proposed algorithm is based on mixed concepts from…

Information Theory · Computer Science 2015-09-22 Frank Ong , Sameer Pawar , Kannan Ramchandran

Linear scaling density functional theory approaches to electronic structure are often based on the tendency of electrons to localize even in large atomic and molecular systems. However, in many cases of actual interest, for example in…

Chemical Physics · Physics 2022-03-25 Marcel David Fabian , Ben Shpiro , Roi Baer

Theoretical material investigation based on density functional theory (DFT) has been a breakthrough in the last century. Nevertheless, the optical properties calculated by DFT generally show poor agreement with experimental results…

Materials Science · Physics 2019-07-17 Mitsutoshi Nishiwaki , Hiroyuki Fujiwara

In many mechanical, electrical, and general physical systems evolving over time or space, spectral analysis methods as Fast Fourier Transform (FFT), Short Term Fourier Transform (STFT), Power Spectrum Density (PSD) plays a very important…

Signal Processing · Electrical Eng. & Systems 2023-06-21 Andreas Tuor , Nico Canzani , Tobias Rüggeberg , Stefan Gorenflo , Gerd Simons , Bruno Bättig , Daniel Iseli

Using the Runge-Gross theorem that establishes the foundation of Time-dependent Density Functional Theory (TDDFT) we prove that for a given electronic Hamiltonian, choice of initial state, and choice of fragmentation, there is a unique…

Chemical Physics · Physics 2015-06-15 Martin A. Mosquera , Daniel Jensen , Adam Wasserman

This work presents a dynamic parallel distribution scheme for the Hartree-Fock exchange~(HFX) calculations based on the real-space NAO2GTO framework. The most time-consuming electron repulsion integrals~(ERIs) calculation is perfectly…

Computational Physics · Physics 2020-09-09 Honghui Shang , Lei Xu , Baodong Wu , Xinming Qin , Yunquan Zhang , Jinlong Yang

Dielectric-dependent hybrid (DDH) functionals were recently shown to yield accurate energy gaps and dielectric constants for a wide variety of solids, at a computational cost considerably less than that of GW calculations. The fraction of…

Materials Science · Physics 2016-06-08 Jonathan H Skone , Marco Govoni , Giulia Galli

The accurate prediction of electronic and optical properties in chalcopyrite semiconductors has been a persistent challenge for density functional theory (DFT) based approaches. Addressing this issue, we demonstrate that very accurate…

Materials Science · Physics 2024-01-31 Arghya Ghosh , Subrata Jana , Dimple Rani , Manoar Hossain , Manish K Niranjan , Prasanjit Samal

Large biomolecular systems, whose function may involve thousands of atoms, cannot easily be addressed with parameter-free density functional theory (DFT) calculations. Until recently a central problem was that such systems possess an…

Materials Science · Physics 2026-01-29 Kristian Berland , Elisa Londero , Elsebeth Schroder , Per Hyldgaard

We present an accurate, efficient and massively parallel finite-element code, DFT-FE, for large-scale ab-initio calculations (reaching $\sim 100,000$ electrons) using Kohn-Sham density functional theory (DFT). DFT-FE is based on a local…

Computational Physics · Physics 2020-01-08 Phani Motamarri , Sambit Das , Shiva Rudraraju , Krishnendu Ghosh , Denis Davydov , Vikram Gavini

In contrast to the original Kohn-Sham (KS) formalism, we propose a density functional theory (DFT) with fractional orbital occupations for the study of ground states of many-electron systems, wherein strong static correlation is shown to be…

Chemical Physics · Physics 2015-06-03 Jeng-Da Chai

We present ab initio calculations of the bandstructure of graphene and of short zigzag graphene nanoribbons by the screened-exchange-LDA method (sX-LDA) within the framework of density functional theory (DFT). The inclusion of non-local…

Mesoscale and Nanoscale Physics · Physics 2012-09-12 Roland Gillen , John Robertson

Density functional theory (DFT) has been actively used and developed recently. DFT is an efficient instrument for describing a wide range of nanoscale phenomena: wetting transition, capillary condensation, adsorption, and others. In this…

Mesoscale and Nanoscale Physics · Physics 2020-07-21 Yuriy Kanygin

We present an accurate and efficient finite-difference formulation and parallel implementation of Kohn-Sham Density (Operator) Functional Theory (DFT) for non periodic systems embedded in a bulk environment. Specifically, employing…

Computational Physics · Physics 2020-11-30 Swarnava Ghosh , Kaushik Bhattacharya

Optical two-dimensional Fourier-transformed (2DFT) spectroscopy is used to study the coherent optical response of potassium vapor in a thin transmission cell. Rephasing and non-rephasing spectra of the D1 and D2 transitions are obtained and…

Atomic Physics · Physics 2011-11-29 X. Dai , A. D. Bristow , D. Karaiskaj , S. T. Cundiff