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

Published: 2013-11-11

Total Pages: 848

ISBN-13: 1489921427

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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.

Electronic Structure and Reactivity of Metal Surfaces

Electronic Structure and Reactivity of Metal Surfaces PDF

Author: E. Derouane

Publisher: Springer Science & Business Media

Published: 2013-03-09

Total Pages: 636

ISBN-13: 1468427962

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Imagine that a young physicist would approach a granting agen cy and propose to contribute to heterogeneous catalysis by studying the heat conductivity of gases in contact with a hot filament. How would he be received now? How would he have been treated sixty years ago ? Yet, more than sixty years ago, Irving Langmuir, through his study of heat transfer from a tungsten filament, uncovered most of the fundamental ideas which are used to-day by the scientific com munity in pure and applied heterogeneous catalysis. Through his work with what were for the first time "clean" metal surfaces, Langmuir formulated during a period of a little over ten years un til the early thirties, the concepts of chemisorption, monolayer, adsorption sites, adsorption isotherm, sticking probability, cata lytic mechanisms by way of the interaction between chemisorbed spe cies, behavior of non-uniform surfaces and repulsion between adsor bed dipoles. It is fair to say that many of these ideas constituting the first revolution in surface chemistry have since been refined through thousands of investigations. Countless papers have been pu blished on the subject of the Langmuir adsorption isotherm, the Langmuir catalytic kinetics and the Langmuir site-exclusion adsorp tion kinetics. The refinements have been significant. ThE original concepts in their primitive or amended form are used everyday by catalytic chemists and chemical engineers allover the world in their treatment of experimental data, design of reactors or inven tion of new processes.

Strong Coulomb Correlations in Electronic Structure Calculations

Strong Coulomb Correlations in Electronic Structure Calculations PDF

Author: Vladimir I Anisimov

Publisher: CRC Press

Published: 2000-05-30

Total Pages: 342

ISBN-13: 9789056991319

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Materials where electrons show nearly localized rather than itinerant behaviour, such as the high-temperature superconducting copper oxides, or manganate oxides, are attracting interest due to their physical properties and potential applications. For these materials, the interaction between electrons, or electron correlation, plays an important role in describing their electronic strucuture, and the standard methods for the calculation of their electronic spectra based on the local density approximation (LDA) breakdown. This is the first attempt to describe recent approaches that go beyond the concept of the LDA, to successfully describe the electronic structure of narrow-band materials.

The Electronic Structure of Complex Systems

The Electronic Structure of Complex Systems PDF

Author: P. Phariseau

Publisher: Springer

Published: 1984

Total Pages: 824

ISBN-13:

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We present here the transcripts of lectures and talks which were delivered at the NATO ADVANCED STUDY INSTITUTE "Electronic Structure of Complex Systems" held at the State University of Ghent, Belgium during the period July 12-23, 1982. The aim of these lectures was to highlight some of the current progress in our understanding of the electronic structure of com plex systems. A massive leap forward is obtained in bandstructure calculations with the advent of linear methods. The bandtheory also profitted tremendously from the recent developments in the density functional theories for the properties of the interacting electron gas in the presence of an external field of ions. The means of per forming fast bandstructure calculations and the confidence in the underlying potential functions have led in the past five years or so to a wealth of investigations into the electronic properties of elemental solids and compounds. The study of the trends of the electronic structure through families of materials provided invalu able insights for the prediction of new materials. The detailed study of the electronic structure of specific solids was not neglected and our present knowledge of d- and f-metals and metal hydrides was reviewed. For those systems we also investi gated the accuracy of the one electron potentials in fine detail and we complemented this with the study of small clusters of atoms where our calculations are amenable to comparison with the frontiers of quantum chemistry calculations.

Electronic Structure, Correlation Effects and Physical Properties of D- and F-metals and Their Compounds

Electronic Structure, Correlation Effects and Physical Properties of D- and F-metals and Their Compounds PDF

Author: Valentin Yu Irkhin

Publisher: Cambridge Int Science Publishing

Published: 2007

Total Pages: 464

ISBN-13: 190460255X

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The book includes all main physical properties of d- and f-transition-metal systems and corresponding theoretical concepts. Special attention is paid to the theory of magnetism and transport phenomena. Some examples of non-traditional questions which are treated in detail in the book: the influence of density of states singularities on electron properties; many-electron description of strong itinerant magnetism; mechanisms of magnetic anisotropy; microscopic theory of anomalous transport phenomena in ferromagnets. Besides considering classical problems of solid state physics as applied to transition metals, modern developments in the theory of correlation effects in d- and f-compounds are considered within many-electron models. The book contains, where possible, a simple physical discussion. More difficult questions are considered in Appendices.

Electron, Spin and Momentum Densities and Chemical Reactivity

Electron, Spin and Momentum Densities and Chemical Reactivity PDF

Author: Paul G. Mezey

Publisher: Springer Science & Business Media

Published: 2006-04-11

Total Pages: 328

ISBN-13: 030646943X

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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.

Electronic Properties of Metals

Electronic Properties of Metals PDF

Author: Gerd Lehmann

Publisher: Elsevier Publishing Company

Published: 1990

Total Pages: 206

ISBN-13:

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The excitation spectrum or band structure of electronics is often interpreted as the electronic structure. This definition is based on the Landau theory of elementary excitations, which shows that the reaction of a many-particle system on a weak external perturbation can be described by nearly non-interacting low-energy excitations of one-particle type. In metals these excitations close to the Fermi energy are only lightly damped. On this basis many electronic properties, especially of metals, can be understood and calculated, a breakthrough which has made a considerable contribution to materials science. This book focuses on the basic principles of solid state physics and in particular on actual problems and recent applications which have not previously been reviewed. At present a common electron theory for all types of solids is developing, unifying the viewing and treatment of the electronic structure and electronic properties of metals and semiconductors.