A bird's-eye view of density-functional theory
TL;DR: In this paper, the authors present an outgrowth of lectures the author gave at the Physics Institute and the Chemistry Institute of the University of Sao Paulo at Sao Carlos, Brazil, and at the VIII'th Summer School on Electronic Structure of the Brazilian Physical Society.
Abstract: This paper is the outgrowth of lectures the author gave at the Physics Institute and the Chemistry Institute of the University of Sao Paulo at Sao Carlos, Brazil, and at the VIII'th Summer School on Electronic Structure of the Brazilian Physical Society. It is an attempt to introduce density-functional theory (DFT) in a language accessible for students entering the field or researchers from other fields. It is not meant to be a scholarly review of DFT, but rather an informal guide to its conceptual basis and some recent developments and advances. The Hohenberg-Kohn theorem and the Kohn-Sham equations are discussed in some detail. Approximate density functionals, selected aspects of applications of DFT, and a variety of extensions of standard DFT are also discussed, albeit in less detail. Throughout it is attempted to provide a balanced treatment of aspects that are relevant for chemistry and aspects relevant for physics, but with a strong bias towards conceptual foundations. The paper is intended to be read before (or in parallel with) one of the many excellent more technical reviews available in the literature.
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TL;DR: This work focuses on the use of range-separated hybrids within a GKS approach as a practical remedy for dealing with the deleterious long-range self-repulsion plaguing many approximate implementations of DFT.
Abstract: We review density functional theory (DFT) within the Kohn-Sham (KS) and the generalized KS (GKS) frameworks from a theoretical perspective for both time-independent and time-dependent problems. We focus on the use of range-separated hybrids within a GKS approach as a practical remedy for dealing with the deleterious long-range self-repulsion plaguing many approximate implementations of DFT. This technique enables DFT to be widely relevant in new realms such as charge transfer, radical cation dimers, and Rydberg excitations. Emphasis is put on a new concept of system-specific range-parameter tuning, which introduces predictive power in applications considered until recently too difficult for DFT.
667 citations
16 May 2019
TL;DR: It is shown how data-driven strategies which include data mining, screening, and machine learning techniques, employ the data generated to uncover complexities and design novel materials with enhanced properties.
Abstract: Recent advances in experimental and computational methods are increasing the quantity and complexity of generated data. This massive amount of raw data needs to be stored and interpreted in order to advance the materials science field. Identifying correlations and patterns from large amounts of complex data is being performed by machine learning (ML) algorithms for decades. Recently, the materials science community started to invest in these methodologies to extract knowledge and insights from the accumulated data. This review follows a logical sequence starting from density functional theory (DFT) as the representative instance of electronic structure methods, to the subsequent high-throughput (HT) approach, used to generate large amounts of data. Ultimately, data-driven strategies which include data mining, screening, and machine learning techniques, employ the data generated. We show how these approaches to modern computational materials science are being used to uncover complexities and design novel materials with enhanced properties. Finally, we point to the present research problems, challenges, and potential future perspectives of this new exciting field.
464 citations
TL;DR: A practical protocol is proposed that allows any scientist—experimental or theoretical—to determine justifiable error estimates for many basic property predictions, without having to perform additional DFT calculations.
Abstract: Predictions of observable properties by density-functional theory calculations (DFT) are used increasingly often by experimental condensed-matter physicists and materials engineers as data. These predictions are used to analyze recent measurements, or to plan future experiments in a rational way. Increasingly more experimental scientists in these fields therefore face the natural question: what is the expected error for such a first-principles prediction? Information and experience about this question is implicitly available in the computational community, scattered over two decades of literature. The present review aims to summarize and quantify this implicit knowledge. This eventually leads to a practical protocol that allows any scientist—experimental or theoretical—to determine justifiable error estimates for many basic property predictions, without having to perform additional DFT calculations. A central role is played by a large and diverse test set of crystalline solids, containing all ground-state...
409 citations
Evgeny Epifanovsky, Andrew T.B. Gilbert1, Andrew T.B. Gilbert2, Xintian Feng3 +235 more•Institutions (54)
TL;DR: The Q-Chem quantum chemistry program package as discussed by the authors provides a suite of tools for modeling core-level spectroscopy, methods for describing metastable resonances, and methods for computing vibronic spectra, the nuclear-electronic orbital method, and several different energy decomposition analysis techniques.
Abstract: This article summarizes technical advances contained in the fifth major release of the Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library of exchange-correlation functionals, along with a suite of correlated many-body methods, continues to be a hallmark of the Q-Chem software. The many-body methods include novel variants of both coupled-cluster and configuration-interaction approaches along with methods based on the algebraic diagrammatic construction and variational reduced density-matrix methods. Methods highlighted in Q-Chem 5 include a suite of tools for modeling core-level spectroscopy, methods for describing metastable resonances, methods for computing vibronic spectra, the nuclear-electronic orbital method, and several different energy decomposition analysis techniques. High-performance capabilities including multithreaded parallelism and support for calculations on graphics processing units are described. Q-Chem boasts a community of well over 100 active academic developers, and the continuing evolution of the software is supported by an "open teamware" model and an increasingly modular design.
360 citations
TL;DR: In this paper, the electronic, optical and electrochemical properties along with electronic behaviors of boron (B) and nitrogen (N) substituted Single Wall Carbon Nanotubes (SWCNTs) underlying density functional theory (DFT) simulations are discussed.
255 citations
References
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Book•
01 Jan 1989TL;DR: In this paper, a review of current studies in density functional theory and density matrix functional theory is presented, with special attention to the possible applications within chemistry, including the concept of an atom in a molecule, calculation of electronegativities from the Xα method, pressure, Gibbs-Duhem equation, Maxwell relations and stability conditions.
Abstract: Current studies in density functional theory and density matrix functional theory are reviewed, with special attention to the possible applications within chemistry. Topics discussed include the concept of electronegativity, the concept of an atom in a molecule, calculation of electronegativities from the Xα method, the concept of pressure, Gibbs-Duhem equation, Maxwell relations, stability conditions, and local density functional theory.
14,008 citations
Book•
01 Sep 2001
TL;DR: A Chemist's Guide to Density Functional Theory should be an invaluable source of insight and knowledge for many chemists using DFT approaches to solve chemical problems.
Abstract: "Chemists familiar with conventional quantum mechanics will applaud and benefit greatly from this particularly instructive, thorough and clearly written exposition of density functional theory: its basis, concepts, terms, implementation, and performance in diverse applications. Users of DFT for structure, energy, and molecular property computations, as well as reaction mechanism studies, are guided to the optimum choices of the most effective methods. Well done!" Paul von RaguE Schleyer "A conspicuous hole in the computational chemist's library is nicely filled by this book, which provides a wide-ranging and pragmatic view of the subject.[...It] should justifiably become the favorite text on the subject for practioneers who aim to use DFT to solve chemical problems." J. F. Stanton, J. Am. Chem. Soc. "The authors' aim is to guide the chemist through basic theoretical and related technical aspects of DFT at an easy-to-understand theoretical level. They succeed admirably." P. C. H. Mitchell, Appl. Organomet. Chem. "The authors have done an excellent service to the chemical community. [...] A Chemist's Guide to Density Functional Theory is exactly what the title suggests. It should be an invaluable source of insight and knowledge for many chemists using DFT approaches to solve chemical problems." M. Kaupp, Angew. Chem.
3,550 citations
Book•
01 Jan 1965
TL;DR: In this paper, the authors developed a propagator theory of Dirac particles, photons, and Klein-Gordon mesons and per-formed a series of calculations designed to illustrate various useful techniques and concepts in electromagnetic, weak, and strong interactions.
Abstract: In this text the authors develop a propagator theory of Dirac particles, photons, and Klein-Gordon mesons and per- form a series of calculations designed to illustrate various useful techniques and concepts in electromagnetic, weak, and strong interactions. these include defining and implementing the renormalization program and evaluating effects of radia- tive corrections, such as the Lamb shift, in low-order calculations. The necessary background for the book is pro- vided by a course in nonrelativistic quantum mechanics at the general level of Schiff's text, QUANTUM MECHANICS.
3,167 citations
05 Mar 2018
TL;DR: In this article, the two-fluid model is used to model elementary excitement in He II and the response to a transverse probe is described as a superfluid flow.
Abstract: * Introduction * Experimental and Theoretical Background on He II. * Elementary Excitations * Elementary Excitations in He II * Superfulid Behavior: Response to a Transverse Probe. Qualitative Behavior of a Superfluid * Superfluid Flow: Macroscopic Limit * Basis for the Two-Fluid Model * First, Second, and Quasi-Particle sound * Vortex Lines * Microscopic Theory: Uniform Condensate * Microscopic Theory: Non-Uniform Condensate * Conclusion
2,717 citations
TL;DR: In this paper, the two-fluid model is used to describe the behavior of a superfluid in response to a transverse probe in a two-fluid model.
Abstract: Special Preface -- Preface -- Special Preface -- Preface -- Introduction -- Neutral Fermi Liquids -- Response and Correlation in Neutral Systems -- Charged Fermi Liquids -- Response and Correlation in Homogeneous Electron Systems -- Microscopic Theories of the Electron Liquid -- Introduction -- Experimental And Theoretical Background On He II -- Elementary Excitations -- Elementary Excitations in He II -- Superfluid Behavior: Response To A Transverse Probe. Qualitative Behavior Of A Superfluid -- Superfluid Flow: Macroscopic Limit -- Basis for the Two-Fluid Model -- First, Second, And Quasi-Particle Sound -- Vortex Lines -- Microscopic Theory: Uniform Condensate -- Microscopic Theory: Non-Uniform Condensate -- Conclusion -- * Second Quantization
2,494 citations