Download or read book Electron Density Distributions In Molecules written by F. L. Hirshfeld and published by CRC Press. This book was released on 1991 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Application of Charge Density Research to Chemistry and Drug Design written by G.A. Jeffrey and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past twenty years, the X-ray crystallography of organic molecules has expanded rapidly in two opposite directions. One is towards larger and larger biological macromolecules and the other is towards the fine details of the electronic structure of small molecules. Both advances required the development of more sophisticated methodologies. Both were made possible by the rapid development of computer technology. X-ray diffraction equipment has responded to these demands, in the one case by the ability to measure quickly many thousands of diffraction spectra, in the other by providing instruments capable of very high precision. Molecules interact through their electrostatic potentials and therefore their experimental and theoretical measurement and calculation is an essential component to understanding the electronic structure of chemical and biochemical reactions. In this ASI, we have brought together experts and their students from both the experimental and theoretical sides of this field, in order that they better understand the philosophy and complexity of these two complementary approaches. George A. Jeffrey Department of Crystallography University of Pittsburgh Pittsburgh, Pennsylvania 15260 USA vii CONTENTS LECTURES General Considerations on Methods for Studying Molecular Structures and Electron Density Distributions ..
Download or read book Electron Densities in Molecular and Molecular Orbitals written by J.R. Van Wazer and published by Elsevier. This book was released on 2012-12-02 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron Densities in Molecules and Molecular Orbitals aims to explain the subject of molecular orbitals without having to rely much on its mathematical aspect, making it more approachable to those who are new to quantum chemistry. The book covers topics such as orbitals in quantum-chemical calculations; electronic ionizations and transitions; molecular-orbital change distributions; orbital transformations and calculations not involving orbitals; and electron densities and shapes in atoms and molecules. Also included in the book are the cross-sectional plots of electron densities of compounds such as organic compounds like methane, ethane, and ethylene; monomeric lithium fluoride and monomeric methyl lithium; hydrogen cyanide and methinophosphide; and monomeric borane and diborane. The text is recommended for those who have begun taking an interest in quantum chemistry but do not wish to deal yet with the mathematics part of the subject.
Download or read book Electron and Magnetization Densities in Molecules and Crystals written by Pierre Becker and published by Springer Science & Business Media. This book was released on 2013-11-21 with total page 885 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interest of describing the ground state properties of a system in terms of one electron density (or its two spin components) is obvious, in particular due to the simple physical significance of this function. Recent experimental progress in diffraction made the measurement of charge and magnetization densities in crystalline solids possible, with an accuracy at least as good as theoretical accuracy. Theoretical developments of the many-body problem have proved the extreme importance of the one electron density function and presently, accurate methods of band structure determination become available. Parallel to the diffraction techniques, other domains of research (inelastic scattering, resonance, molecular spectroscopy) deal with quantities directly related to the one particle density. But the two types of studies do not interfere enough and one should obviously gain more information by interpreting all experiments that are related to the density together. It became necessary to have an International School that reviews the status of the art in the domain of "ELECTRON AND MAGNETIZATION DENSITIES IN MOLECULES AND CRYSTALS". This was made possible through the generous effort of N.A.T.O. 's Scientific Affairs Division, and I would specially thank Dr. T. KESTER, the head of this Division, for his help and competence. An Advanced Study Institute was thus held in ARLES, south France, from the 16th to the 31st of August 1978.
Download or read book The Fundamentals of Electron Density Density Matrix and Density Functional Theory in Atoms Molecules and the Solid State written by N.I. Gidopoulos and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume records the proceedings of a Forum on The Fundamentals of Electron Density, Density Matrix and Density Functional Theory in Atoms, Molecules and the Solid State held at the Coseners' House, Abingdon-on-Thames, Oxon. over the period 31st May - 2nd June, 2002. The forum consisted of 26 oral and poster presentations followed by a discussion structure around questions and comments submitted by the participants (and others who had expressed an interest) in advance of the meeting. Quantum mechanics provides a theoretical foundation for our under standing of the structure and properties of atoms, molecules and the solid state in terms their component particles, electrons and nuclei. (Rel ativistic quantum mechanics is required for molecular systems contain ing heavy atoms.) However, the solution of the equations of quantum mechanics yields a function, a wave function, which depends on the co ordinates, both space and spin, of all of the particles in the system. This functions contains much more information than is required to yield the energy or other property.
Download or read book A Matter of Density written by N. Sukumar and published by John Wiley & Sons. This book was released on 2012-09-18 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origins and significance of electron density in the chemical, biological, and materials sciences Electron density is one of the fundamental concepts underlying modern chemistry and one of the key determinants of molecular structure and stability. It is also the basic variable of density functional theory, which has made possible, in recent years, the application of the mathematical theory of quantum physics to chemical and biological systems. With an equal emphasis on computational and philosophical questions, A Matter of Density: Exploring the Electron Density Concept in the Chemical, Biological, and Materials Sciences addresses the foundations, analysis, and applications of this pivotal chemical concept. The first part of the book presents a coherent and logically connected treatment of the theoretical foundations of the electron density concept. Discussion includes the use of probabilities in statistical physics; the origins of quantum mechanics; the philosophical questions at the heart of quantum theory, like quantum entanglement; and methods for the experimental determination of electron density distributions. The remainder of the book deals with applications of the electron density concept in the chemical, biological, and materials sciences. Contributors offer insights on how a deep understanding of the origins of chemical reactivity can be gleaned from the concepts of density functional theory. Also discussed are the applications of electron density in molecular similarity analysis and electron density-derived molecular descriptors, such as electrostatic potentials and local ionization energies. This section concludes with some applications of modern density functional theory to surfaces and interfaces. An essential reference for students as well as quantum and computational chemists, physical chemists, and physicists, this book offers an unparalleled look at the development of the concept of electron density from its inception to its role in density functional theory, which led to the 1998 Nobel Prize in Chemistry.
Download or read book Electron Density Distributions in Weak Interactions written by Thi Thanh Ha Nguyen and published by . This book was released on 2008 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Spin and Momentum Densities and Chemical Reactivity written by Paul G. Mezey and published by Springer Science & Business Media. This book was released on 2006-04-11 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The electron density of a non-degenerate ground state system determines essentially all physical properties of the system. This statement of the Hohenberg–Kohn theorem of Density Functional Theory plays an exceptionally important role among all the fundamental relations of Molecular Physics. In particular, the electron density distribution and the dynamic properties of this density determine both the local and global reactivities of molecules. High resolution experimental electron densities are increasingly becoming available for more and more molecules, including macromolecules such as proteins. Furthermore, many of the early difficulties with the determination of electron densities in the vicinity of light nuclei have been overcome. These electron densities provide detailed information that gives important insight into the fundamentals of molecular structure and a better understanding of chemical reactions. The results of electron density analysis are used in a variety of applied fields, such as pharmaceutical drug discovery and biotechnology. If the functional form of a molecular electron density is known, then various molecular properties affecting reactivity can be determined by quantum chemical computational techniques or alternative approximate methods.
Download or read book Electron Density and Bonding in Crystals written by V.G Tsirelson and published by CRC Press. This book was released on 2020-11-25 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron Density and Bonding in Crystals: Principles, Theory and X-Ray Diffraction Experiments in Solid State Physics and Chemistry provides a comprehensive, unified account of the use of diffraction techniques to determine the distribution of electrons in crystals. The book discusses theoretical and practical techniques, the application of electron density studies to chemical bonding, and the determination of the physical properties of condensed matter. The book features the authors' own key contributions to the subject as well a thorough, critical summary of the extensive literature on electron density and bonding. Logically organized, coverage ranges from the theoretical and experimental basis of electron density determination to its impact on investigations of the nature of the chemical bond and its uses in determining electromagnetic and optical properties of crystals. The main text is supplemented by appendices that provide clear, concise guidance on aspects such as systems of units, quantum theory of atomic vibrations, atomic orbitals, and creation and annihilation operators. The result is a valuable compendium of modern knowledge on electron density distributions, making this reference a standard for crystallographers, condensed matter physicists, theoretical chemists, and materials scientists.
Download or read book On the Electron Density Distribution in Molecular Complexes written by Harold Bruning and published by . This book was released on 1992 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Distributions and the Chemical Bond written by Philip Coppens and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book represents the proceedings of a symposium held at the Spring 1981 ACS meeting in Atlanta. The symposium brought together Theoretical Chemists, Solid State Physicists, Experimen tal Chemists and Crystallographers. One of its major aims was to increase interaction between these diverse groups which often use very different languages to describe similar concepts. The devel opment of a common language, or at least the acquisition of a multilingual capability, is a necessity if the field is to prosper. Much depends in this field on the interplay between theory and experiment. Accordingly this volume begins with two introduc tory chapters, one theoretical and the other experimental, which contain much of the background material needed for a through under standing of the field. The remaining sections describe a wide variety of applications and illustrate, we believe, the central role of charge densities in the understanding of chemical bonding. We are most indebted to the Divisions of Inorganic and Phy sical Chemistry of the American Chemical Society, which provided the stimulus for the symposium and gave generous financial support. We also gratefully acknowledge financial support from the Special Educational Opportunities Program of the Petroleum Research Fund administered by the American Chemical Society, which made exten sive participation by speakers from abroad possible.
Download or read book Charge Distributions and Chemical Effects written by S. Fliszar and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: The energy of a molecule can be studied with the help of quantum theory, a satisfactory approach because it involves only basic and clearly identified physical concepts. In an entirely different approach, the molecular energy can be broken down into individual contributions reflecting chemical bonds plus a host of subsidiary "effects", like y-gauche, skew pentane, ring-strain, etc. , giving an overall picture in terms of topological characteristics. The latter approach can be successful, particularly if a sufficient number of particular topological situations have been parametrized (which is an empir ical way of "understanding" chemistry), but also contains the seed for difficulties. Indeed, the danger exists of unduly ascribing a physical meaning to corrective terms whose function is primarily to account in an empirical fashion for discrepancies between "expected" and observed results. The link between this type of empirical approach and the knowledge that the ground state energy is uniquely determined by the electron density is lost somewhere along the road, although some of the "steric effects" are here and there vaguely traced back to electronic effects. The approach presented in this monograph goes back to the fundamen tals in that it is exclusively based on interactions involving nuclear and electronic charges. Confining the study to molecules in their equilibrium geometry, the problem of molecular energies is reduced to its electrostatic aspects, explicitly involving local electron populations.
Download or read book Atomic Structure Theory written by Walter R. Johnson and published by Springer Science & Business Media. This book was released on 2007-03-08 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a hands-on experience with atomic structure calculations. Material covered includes angular momentum methods, the central field Schrödinger and Dirac equations, Hartree-Fock and Dirac-Hartree-Fock equations, multiplet structure, hyperfine structure, the isotope shift, dipole and multipole transitions, basic many-body perturbation theory, configuration interaction, and correlation corrections to matrix elements. The book also contains numerical methods for solving the Schrödinger and Dirac eigenvalue problems and the (Dirac)-Hartree-Fock equations.
Download or read book Information Theory of Molecular Systems written by Roman F Nalewajski and published by Elsevier. This book was released on 2006-03-31 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: As well as providing a unified outlook on physics, Information Theory (IT) has numerous applications in chemistry and biology owing to its ability to provide a measure of the entropy/information contained within probability distributions and criteria of their information "distance" (similarity) and independence. Information Theory of Molecular Systems applies standard IT to classical problems in the theory of electronic structure and chemical reactivity. The book starts by introducing the basic concepts of modern electronic structure/reactivity theory based upon the Density Functional Theory (DFT), followed by an outline of the main ideas and techniques of IT, including several illustrative applications to molecular systems. Coverage includes information origins of the chemical bond, unbiased definition of molecular fragments, adequate entropic measures of their internal (intra-fragment) and external (inter-fragment) bond-orders and valence-numbers, descriptors of their chemical reactivity, and information criteria of their similarity and independence. Information Theory of Molecular Systems is recommended to graduate students and researchers interested in fresh ideas in the theory of electronic structure and chemical reactivity.·Provides powerful tools for tackling both classical and new problems in the theory of the molecular electronic structure and chemical reactivity·Introduces basic concepts of the modern electronic structure/reactivity theory based upon the Density Functional Theory (DFT)·Outlines main ideas and techniques of Information Theory
Download or read book From X ray Structure Factors to Electron density Distributions written by P. Louca and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Density Functional Theory of Molecules Clusters and Solids written by D.E. Ellis and published by Springer Science & Business Media. This book was released on 1995 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid advances are taking place in the application of density functional theory (DFT) to describe complex electronic structures, to accurately treat large systems and to predict physical and chemical properties. Both theoretical content and computational methodology are developing at a pace which offers researchers new opportunities in areas such as quantum chemistry, cluster science, and solid state physics. This volume contains ten contributions by leading scientists in the field and provides an authoritative overview of the most important developments. The book focuses on the following themes: determining adequate approximations for the many-body problem of electronic correlations; how to transform these approximations into computational algorithms; applications to discover and predict properties of electronic systems; and developing the theory. For researchers in surface chemistry, catalysis, ceramics and inorganic chemistry.
Download or read book Electron Density and Chemical Bonding I written by Dietmar Stalke and published by Springer. This book was released on 2012-06-05 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: D. Stalke, U. Flierler: More than Just Distances from Electron Density Studies.- A.O. Madsen: Modeling and Analysis of Hydrogen Atoms.- B.B. Iversen/J. Overgaard: Charge Density Methods in Hydrogen Bond Studies.- U. Flierler, D. Stalke: Some Main Group Chemical Perceptions in the Light of Experimental Charge Density Investigations.- D. Leusser: Electronic Structure and Chemical Properties of Lithium Organics Seen Through the Glasses of Charge Density.- L. J. Farrugia, P. Macchi: Bond Orders in Metal–Metal Interactions Through Electron Density Analysis.- W. Scherer, V. Herz, Ch. Hauf: On the Nature of β-Agostic Interactions: A Comparison Between the Molecular Orbital and Charge Density Picture.
