Local Density Approximations in Quantum Chemistry and Solid State Physics

Local Density Approximations in Quantum Chemistry and Solid State Physics PDF Author: Jens Peder Dahl
Publisher: Springer Science & Business Media
ISBN: 1489921427
Category : Science
Languages : en
Pages : 848

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Book Description
The· simplest picture of an atom, a molecule or a solid is the picture of its distribution of charge. It is obtained by specifying the positions of the atomic nuclei and by showing how the density, p(E), of the electronic charge-cloud varies from place to place. A much more detailed picture is provided by the many-electron wavefunction. This quantity shows not only the arrangement of the electrons with respect to the nuclei, but also the arrangement of the electrons with respect to each other, and it allows the evaluation of the total energy and other properties. The many-electron wavefunction is in principle obtained by solving the many-electron Schrodinger equation for the motion of the interacting electrons under the influ ence of the nuclei, but in practice the equation is unsolvable, and it is necessary to proceed by methods of approximation. Needless to say, .such methods will as a rule depend on the complexity of the system considered.

Local Density Approximations in Quantum Chemistry and Solid State Physics

Local Density Approximations in Quantum Chemistry and Solid State Physics PDF Author: Jens Peder Dahl
Publisher: Springer Science & Business Media
ISBN: 1489921427
Category : Science
Languages : en
Pages : 848

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Book Description
The· simplest picture of an atom, a molecule or a solid is the picture of its distribution of charge. It is obtained by specifying the positions of the atomic nuclei and by showing how the density, p(E), of the electronic charge-cloud varies from place to place. A much more detailed picture is provided by the many-electron wavefunction. This quantity shows not only the arrangement of the electrons with respect to the nuclei, but also the arrangement of the electrons with respect to each other, and it allows the evaluation of the total energy and other properties. The many-electron wavefunction is in principle obtained by solving the many-electron Schrodinger equation for the motion of the interacting electrons under the influ ence of the nuclei, but in practice the equation is unsolvable, and it is necessary to proceed by methods of approximation. Needless to say, .such methods will as a rule depend on the complexity of the system considered.

Quantal Density Functional Theory II

Quantal Density Functional Theory II PDF Author: Viraht Sahni
Publisher: Springer Science & Business Media
ISBN: 3540922296
Category : Science
Languages : en
Pages : 426

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Book Description
In my original proposal to Springer for a book on Quantal Density Functional Theory, I had envisaged one that was as complete in its presentation as possible, describing the basic theory as well as the approximation methods and a host of applications. However,after workingon the bookforabout ?ve years, I realizedthat the goal was too ambitious, and that I would be writing for another ?ve years for it to be achieved. Fortunately,there was a natural breakin the material, and I proposed to my editor, Dr. Claus Ascheron, that we split the book into two components: the ?rst on the basic theoretical framework, and the second on approximation methods and applications. Dr. Ascheron consented, and I am thankful to him for agreeing to do so. Hence, we published Quantal Density Functional Theory in 2004, and are now publishing Quantal Density Functional Theory II: Approximation Methods and Applications. One signi?cant advantage of this, as it turns out, is that I have been able to incorporate in each volume the most recent understandings available. This volume, like the earlier one, is aimed at advanced undergraduates in physics and chemistry, graduate students and researchers in the ?eld. It is written in the same pedagogical style with details of all proofs and numerous ?gures provided to explain the physics. The book is independent of the ?rst volume and stands on its own. However, proofs given in the ?rst volume are not repeated here.

Density Functional Methods in Chemistry

Density Functional Methods in Chemistry PDF Author: Jan K. Labanowski
Publisher: Springer Science & Business Media
ISBN: 1461231361
Category : Science
Languages : en
Pages : 444

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Book Description
Predicting molecular structure and energy and explaining the nature of bonding are central goals in quantum chemistry. With this book, the editors assert that the density functional (DF) method satisfies these goals and has come into its own as an advanced method of computational chemistry. The wealth of applications presented in the book, ranging from solid state sys tems and polymers to organic and organo-metallic molecules, metallic clus ters, and biological complexes, prove that DF is becoming a widely used computational tool in chemistry. Progress in the methodology and its imple mentation documented by the contributions in this book demonstrate that DF calculations are both accurate and efficient. In fact, the results of DF calculations may pleasantly surprise many chem ists. Even the simplest approximation of DF, the local spin density method (LSD), yields molecular structures typical of ab initio correlated methods. The next level of theory, the nonlocal spin density method, predicts the energies of molecular processes within a few kcallmol or less. Like the Hartree-Fock (HF) and configuration interaction (CI) methods, the DF method is based only on fundamental physical constants. Therefore, it does not require semiempirical parameters and can be applied to any molecular system and to metallic phases. However, DF's greatest advantage is that it can be applied to much larger systems than those approachable by tradition al ab initio methods, especially when compared with correlated ab initio methods.

Density Functional Theory

Density Functional Theory PDF Author: Source Wikipedia
Publisher: University-Press.org
ISBN: 9781230537641
Category :
Languages : en
Pages : 24

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Book Description
Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 22. Chapters: ABINIT, Atomistix ToolKit, Atomistix Virtual NanoLab, BigDFT, Car-Parrinello method, Car-Parrinello molecular dynamics, CASTEP, CONQUEST, CP2K, Electronic density, EXCITING, Hybrid functional, Jellium, Kohn-Sham equations, Lattice density functional theory, List of quantum chemistry and solid-state physics software, Local-density approximation, ONETEP, Orbital-free density functional theory, PARSEC, Pulay Stress, PWscf, Quantum ESPRESSO, Runge-Gross theorem, SIESTA (computer program), Thomas-Fermi model, Time-dependent density functional theory, Vienna Ab-initio Simulation Package, WIEN2k. Excerpt: Density functional theory (DFT) is a quantum mechanical modelling method used in physics and chemistry to investigate the electronic structure (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases. With this theory, the properties of a many-electron system can be determined by using functionals, i.e. functions of another function, which in this case is the spatially dependent electron density. Hence the name density functional theory comes from the use of functionals of the electron density. DFT is among the most popular and versatile methods available in condensed-matter physics, computational physics, and computational chemistry. DFT has been very popular for calculations in solid-state physics since the 1970s. However, DFT was not considered accurate enough for calculations in quantum chemistry until the 1990s, when the approximations used in the theory were greatly refined to better model the exchange and correlation interactions. In many cases the results of DFT calculations for solid-state systems agree quite satisfactorily with experimental data. Computational costs are relatively low when compared to traditional methods, such as Hartree-Fock...

Energy Density Functional Theory of Many-Electron Systems

Energy Density Functional Theory of Many-Electron Systems PDF Author: Eugene S. Kryachko
Publisher: Springer Science & Business Media
ISBN: 9400919700
Category : Science
Languages : en
Pages : 862

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Book Description


From Micro To Macro Quantum Systems: A Unified Formalism With Superselection Rules And Its Applications

From Micro To Macro Quantum Systems: A Unified Formalism With Superselection Rules And Its Applications PDF Author: K Kong Wan
Publisher: World Scientific
ISBN: 1783260017
Category : Science
Languages : en
Pages : 709

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Book Description
Traditional quantum theory has a very rigid structure, making it difficult to accommodate new properties emerging from novel systems. This book presents a flexible and unified theory for physical systems, from micro and macro quantum to classical. This is achieved by incorporating superselection rules and maximal symmetric operators into the theory. The resulting theory is applicable to classical, microscopic quantum and non-orthodox mixed quantum systems of which macroscopic quantum systems are examples. A unified formalism also greatly facilitates the discussion of interactions between these systems. A scheme of quantization by parts is introduced, based on the mathematics of selfadjoint and maximal symmetric extensions of symmetric operators, to describe point interactions. The results are applied to treat superconducting quantum circuits in various configurations.This book also discusses various topics of interest such as the asymptotic treatment of quantum state preparation and quantum measurement, local observables and local values, Schrödinger's cat states in superconducting systems, and a path space formulation of quantum mechanics.This self-contained book is complete with a review of relevant geometric and operator theories, for example, vector fields and operators, symmetric operators and their maximal symmetric extensions, direct integrals of Hilbert spaces and operators./a

Molecules in Physics, Chemistry, and Biology

Molecules in Physics, Chemistry, and Biology PDF Author: Jean Maruani
Publisher: Springer Science & Business Media
ISBN: 9789027725981
Category : Science
Languages : en
Pages : 466

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Book Description
Volume 1: General Introduction to Molecular Sciences Volume 2: Physical Aspects of Molecular Systems Volume 3: Electronic Structure and Chemical Reactivity Volume 4: Molecular Phenomena in Biological Sciences

Molecules in Physics, Chemistry, and Biology

Molecules in Physics, Chemistry, and Biology PDF Author: J. Maruani
Publisher: Springer Science & Business Media
ISBN: 940092853X
Category : Science
Languages : en
Pages : 442

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Book Description
Volume 1: General Introduction to Molecular Sciences Volume 2: Physical Aspects of Molecular Systems Volume 3: Electronic Structure and Chemical Reactivity Volume 4: Molecular Phenomena in Biological Sciences

Mathematical Challenges from Theoretical/Computational Chemistry

Mathematical Challenges from Theoretical/Computational Chemistry PDF Author: National Research Council
Publisher: National Academies Press
ISBN: 030917662X
Category : Mathematics
Languages : en
Pages : 143

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Book Description
Computational methods are rapidly becoming major tools of theoretical, pharmaceutical, materials, and biological chemists. Accordingly, the mathematical models and numerical analysis that underlie these methods have an increasingly important and direct role to play in the progress of many areas of chemistry. This book explores the research interface between computational chemistry and the mathematical sciences. In language that is aimed at non-specialists, it documents some prominent examples of past successful cross-fertilizations between the fields and explores the mathematical research opportunities in a broad cross-section of chemical research frontiers. It also discusses cultural differences between the two fields and makes recommendations for overcoming those differences and generally promoting this interdisciplinary work.

Computational Chemistry

Computational Chemistry PDF Author: David Young
Publisher: John Wiley & Sons
ISBN: 0471458430
Category : Science
Languages : en
Pages : 408

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Book Description
A practical, easily accessible guide for bench-top chemists, thisbook focuses on accurately applying computational chemistrytechniques to everyday chemistry problems. Provides nonmathematical explanations of advanced topics incomputational chemistry. Focuses on when and how to apply different computationaltechniques. Addresses computational chemistry connections to biochemicalsystems and polymers. Provides a prioritized list of methods for attacking difficultcomputational chemistry problems, and compares advantages anddisadvantages of various approximation techniques. Describes how the choice of methods of software affectsrequirements for computer memory and processing time.