Electron Correlation in Molecules

Electron Correlation in Molecules PDF Author: S. Wilson
Publisher: Courier Corporation
ISBN: 0486150224
Category : Science
Languages : en
Pages : 305

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Book Description
Electron correlation effects are of vital significance to the calculation of potential energy curves and surfaces, the study of molecular excitation processes, and in the theory of electron-molecule scattering. This text describes methods for addressing one of theoretical chemistry's central problems, the study of electron correlation effects in molecules. Although the energy associated with electron correlation is a small fraction of the total energy of an atom or molecule, it is of the same order of magnitude as most energies of chemical interest. If the solution of quantum mechanical equations from first principles is to provide an accurate quantitative prediction, reliable techniques for the theoretical determination of the effect of electron correlation on molecular properties are therefore important. To that end, this text explores molecular electronic structure, independent electron models, electron correlation, the linked diagram theorem, group theoretical aspects, the algebraic approximation, and truncation of expansions for expectation values.

Electron Correlation in Molecules

Electron Correlation in Molecules PDF Author: S. Wilson
Publisher: Courier Corporation
ISBN: 0486150224
Category : Science
Languages : en
Pages : 305

Get Book

Book Description
Electron correlation effects are of vital significance to the calculation of potential energy curves and surfaces, the study of molecular excitation processes, and in the theory of electron-molecule scattering. This text describes methods for addressing one of theoretical chemistry's central problems, the study of electron correlation effects in molecules. Although the energy associated with electron correlation is a small fraction of the total energy of an atom or molecule, it is of the same order of magnitude as most energies of chemical interest. If the solution of quantum mechanical equations from first principles is to provide an accurate quantitative prediction, reliable techniques for the theoretical determination of the effect of electron correlation on molecular properties are therefore important. To that end, this text explores molecular electronic structure, independent electron models, electron correlation, the linked diagram theorem, group theoretical aspects, the algebraic approximation, and truncation of expansions for expectation values.

Theoretical Methods for Strongly Correlated Electrons

Theoretical Methods for Strongly Correlated Electrons PDF Author: David Sénéchal
Publisher: Springer Science & Business Media
ISBN: 0387217177
Category : Science
Languages : en
Pages : 362

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Book Description
Focusing on the purely theoretical aspects of strongly correlated electrons, this volume brings together a variety of approaches to models of the Hubbard type - i.e., problems where both localized and delocalized elements are present in low dimensions. The chapters are arranged in three parts. The first part deals with two of the most widely used numerical methods in strongly correlated electrons, the density matrix renormalization group and the quantum Monte Carlo method. The second part covers Lagrangian, Functional Integral, Renormalization Group, Conformal, and Bosonization methods that can be applied to one-dimensional or weakly coupled chains. The third part considers functional derivatives, mean-field, self-consistent methods, slave-bosons, and extensions.

New Electron Correlation Methods and Their Applications, and Use of Atomic Orbitals with Exponential Asymptotes

New Electron Correlation Methods and Their Applications, and Use of Atomic Orbitals with Exponential Asymptotes PDF Author: Monika Musial
Publisher: Elsevier
ISBN: 0128235462
Category : Science
Languages : en
Pages : 352

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Book Description
Advances in Quantum Chemistry presents surveys of current topics in this rapidly developing field one that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry, and biology. It features detailed reviews written by leading international researchers. In this volume the readers are presented with an exciting combination of themes. Presents surveys of current topics in this rapidly-developing field that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry and biology Features detailed reviews written by leading international researchers

Electron Correlation in Molecules and Condensed Phases

Electron Correlation in Molecules and Condensed Phases PDF Author: Norman H. March
Publisher: Springer Science & Business Media
ISBN: 148991370X
Category : Science
Languages : en
Pages : 404

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Book Description
This book had its origins in lectures presented at EPFL, Lausanne, during two separate visits (the most recent being to IRRMA). The author is most grateful to Professors A. Baldereschi, R. Car, and A. Quattropani for making these visits possible, and for the splendidly stimulating environment provided. Professors S. Baroni and R. Resta also influenced considerably the presentation of material by constructive help and comments. Most importantly, Chapters 4 and 5 were originally prepared for a review article by Professor G. Senatore, then at Pavia and now in Trieste, and myself for Reviews of Modem Physics (1994). In the 'course of this collaboration, he has taught me a great deal, especially about quantum Monte Carlo procedures, and Chapter 5 is based directly on this review article. Also in Chapter 4, my original draft on Gutzwiller's method has been transformed by his deeper understanding; again this is reflected directly in Chapter 4; especially in the earlier sections. In addition to the above background, it is relevant here to point out that, as a backcloth for the present, largely "state of the art," account, there are two highly relevant earlier books: The Many-body Problem in Quantum Mechanics with W.

Lecture Notes on Electron Correlation and Magnetism

Lecture Notes on Electron Correlation and Magnetism PDF Author: Patrik Fazekas
Publisher: World Scientific
ISBN: 9810224745
Category : Science
Languages : en
Pages : 794

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Book Description
Readership: Graduate students and researchers in condensed matter physics.

Electron Correlations in Molecules and Solids

Electron Correlations in Molecules and Solids PDF Author: Peter Fulde
Publisher: Springer Science & Business Media
ISBN: 3642578098
Category : Science
Languages : en
Pages : 492

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Book Description
Dieser Titel verbindet die Festkörpertheorie mit der Quantenchemie. Neue Konzepte der Vielteilchen-Verarbeitung und Korrelations-Effekte, normale quantenchemische Verfahren mit Projektionstechniken, Greensche Funktionen und Monte-Carlo-Methoden werden erarbeitet. Anwendungsbereiche der Molekültheorie, von Halbleitern, supraleitender high-Tc-Materialien, etc., werden vorgestellt.

New Electron Correlation Methods and their Applications, and Use of Atomic Orbitals with Exponential Asymptotes

New Electron Correlation Methods and their Applications, and Use of Atomic Orbitals with Exponential Asymptotes PDF Author:
Publisher: Academic Press
ISBN: 0128235470
Category : Science
Languages : en
Pages : 354

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Book Description
Advances in Quantum Chemistry presents surveys of current topics in this rapidly developing field one that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry, and biology. It features detailed reviews written by leading international researchers. In this volume the readers are presented with an exciting combination of themes. Presents surveys of current topics in this rapidly-developing field that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry and biology Features detailed reviews written by leading international researchers

Correlated Electrons in Quantum Matter

Correlated Electrons in Quantum Matter PDF Author: Peter Fulde
Publisher: World Scientific
ISBN: 9814397229
Category : Science
Languages : en
Pages : 552

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Book Description
An understanding of the effects of electronic correlations in quantum systems is one of the most challenging problems in physics, partly due to the relevance in modern high technology. Yet there exist hardly any books on the subject which try to give a comprehensive overview on the field covering insulators, semiconductors, as well as metals. The present book tries to fill that gap. It intends to provide graduate students and researchers a comprehensive survey of electron correlations, weak and strong, in insulators, semiconductors and metals. This topic is a central one in condensed matter and beyond that in theoretical physics. The reader will have a better understanding of the great progress which has been made in the field over the past few decades. Contents:IntroductionIndependent ElectronsHomogeneous Electron GasDensity Functional TheoryWavefunction-Based MethodsCorrelated Ground-State WavefunctionsQuasiparticle ExcitationsIncoherent ExcitationsCoherent-Potential ApproximationsStrongly Correlated ElectronsTransition MetalsTransition-Metal OxidesHeavy QuasiparticlesExcitations with Fractional ChargesSuperconductivity Readership: Graduate students and researchers in condensed matter physics. Keywords:Electron Correlations;Many-body Theory;Quasi-Particles;Fractional Charges;Superconductivity;Many-Body WavefunctionsKey Features:Besides approaches based on Density Functional Theory, the importance of many-body wavefunction and projection methods is emphasizedConsiderable space is devoted to systems with strong electron correlations evident in high-Tc superconducting cupratesTransition metals and their oxides are discussed as well as compounds with heavy quasiparticlesDifferent competing methods for describing correlation effects are presentedAt various places a connection to relevant experiments is madeReviews: “Peter Fulde's book is well suited as an introduction to the general field of correlated electron systems… For this purpose some elementary chapters are included. Finally, the book is hard work but also fun to read because of its personal style.” Prof. Dr. Joachim Keller Institut für Theoretische Physik Universität Regensburg “Written with great pedagogical skill, it will be of interest to both experts in the field and graduate students. The book presents a consistent description of a new branch of solid state physics — the theory of strongly correlated systems which cannot be treated by conventional approaches as the density functional theory being successful for many years in describing band structure of solids. In this respect it can be used as a textbook for a university course on this new and fascinating branch of solid state physics.” Professor Nikolay Pladika Joint Institute for Nuclear Research “Peter Fulde provides an excellent introduction to this field. This book provides a very careful treatment of an extraordinarily wide range of topics, and is particularly strong on transition-metal oxides and heavy fermion systems. This carefully written book can be recommended to a very wide readership.” Contemporary Physics

Electron Correlation Methodology

Electron Correlation Methodology PDF Author: Angela K. Wilson
Publisher:
ISBN:
Category : Language Arts & Disciplines
Languages : en
Pages : 236

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Book Description
Modeling is becoming a significant component in the design and analysis of chemical systems in areas such as catalysis, nanomaterials, and biological systems. With rapidly advancing technology, there is an increasing need to model molecules that are quite large and complex, and to model such systems with reasonable accuracy. However, computational methods are generally more numerous and reliable for lighter, smaller molecules since calculations on smaller molecules are less computationally demanding than for larger molecules, and can take advantage of high accuracy, but prohibitively expensive, computational approaches. Two widely used approaches for chemical modeling are ab initio correlated methods and density functional theory. Though there is great interest in using these methods for high accuracy calculations on increasingly larger and more complex chemical systems, each approach currently has limitations. Ab initio methods suffer from a high "N-scaling" problem, where the N-scaling represents the computational cost (memory, disk space, and time requirements of the calculations), thus making high accuracy calculations. Density functional methods have a much lower N-scaling, and thus calculations can be done on much larger molecules. Unfortunately, density functional calculations are generally not as reliable as ab initio approaches, and sometimes, at best can only provide a qualitative description of properties of interest. This volume brings together researchers from throughout the world to assess recent progress in the field of electronic structure methodology, focusing upon ab initio and density functional developments, and to discuss future direction. This publication will impact a number of fields including computational chemistry, organic chemistry, and inorganic chemistry. It will help to provide a closer commonality of ab initio and density functional approaches, as it brings together many of the top senior and junior scientists in both fields to address a common problem: high accuracy modeling of larger chemical systems.

Methods in Computational Chemistry

Methods in Computational Chemistry PDF Author: Stephen Wilson
Publisher: Springer Science & Business Media
ISBN: 148991983X
Category : Science
Languages : en
Pages : 378

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Book Description
When, forty years ago, as a student of Charles Coulson in Oxford I began work in theoretical chemistry, I was provided with a Brunsviga calculator-a small mechanical device with a handle for propulsion, metal levers for setting the numbers, and a bell that rang to indicate overflow. What has since come to be known as computational chemistry was just beginning. There followed a long period in which the fundamental theory of the "golden age" (1925-1935) was extended and refined and in which the dreams of the early practitioners were gradually turned into hard arithmetic reality. As a still-computing survivor from the early postwar days now enjoying the benefits of unbelievably improved hardware, I am glad to contribute a foreword to this series and to have the opportunity of providing a little historical perspective. After the Brunsviga came the electromechanical machines of the late 1940s and early 1950s, and a great reduction in the burden of calculating molecular wavefunctions. We were now happy. At least for systems con taining a few electrons it was possible to make fully ab initio calculations, even though semiempirical models remained indispensable for most molecules of everyday interest. The 1950 papers of Hall and of Roothaan represented an important milestone along the road to larger-scale non empirical calculations, extending the prewar work of Hartree and Fock from many-electron atoms to many-electron molecules-and thus into "real chemistry.