Download or read book Electronic Structure Methods for Complex Materials written by Wai-Yim Ching and published by OUP Oxford. This book was released on 2012-05-17 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Density functional theory (DFT) has blossomed in the past few decades into a powerful tool that is used by experimentalists and theoreticians alike. This book highlights the extensive contributions that the DFT-based OLCAO method has made to progress in this field, and it demonstrates its competitiveness for performing ab initio calculations on large and complex models of practical systems. A brief historical account and introduction to the elements of the theory set the stage for discussions on semiconductors, insulators, crystalline metals and alloys, complex crystals, non-crystalline solids and liquids, microstructure containing systems and those containing impurities, defects, and surfaces, biomolecular systems, and the technique of ab initio core level spectroscopy calculation.
Download or read book Optimized LCAO Method and the Electronic Structure of Extended Systems written by Helmut Eschrig and published by Springer. This book was released on 2012-12-06 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical and numerical details of an optimized LCAO (linear combination of atomic orbitals) method for the calculation of self-consistent bandstructures are given together with a variety of examples. The method will be a valuable tool both for researchers engaged in calculations and for scientists looking for numerical results of self-consistent bandstructure calculations. The presentation starts with an introduction to the modern many-body theory of electronic bandstructure. The essentials of the representation with a non-orthogonal basis and the usual tight-binding variants are critically reviewed. A variational approach to the optimization of atom-like basis orbitals is described together with an SCF procedure for band calculations. Complete numerical and graphic results for all elementary metals from lithium to zinc are given.
Download or read book Electronic Structure Methods for Complex Materials written by Wai-Yim Ching and published by Oxford University Press. This book was released on 2012-05-17 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book details the application of the OLCAO method for calculating the properties of solids from fundamental principles to a wide array of material systems. The method specializes in large and complex models and is able to compute a variety of useful properties including electronic, optical, and spectroscopic properties.
Download or read book Ab Initio Valence Calculations in Chemistry written by D. B. Cook and published by Butterworth-Heinemann. This book was released on 2013-10-22 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ab Initio Valence Calculations in Chemistry describes the theory and practice of ab initio valence calculations in chemistry and applies the ideas to a specific example, linear BeH2. Topics covered include the Schrödinger equation and the orbital approximation to atomic orbitals; molecular orbital and valence bond methods; practical molecular wave functions; and molecular integrals. Open shell systems, molecular symmetry, and localized descriptions of electronic structure are also discussed. This book is comprised of 13 chapters and begins by introducing the reader to the use of the Schrödinger equation to solve the electronic structure of molecular systems. This discussion is followed by two chapters that describe the chemical and mathematical nature of orbital theories in quantum chemistry. Two general ways of using chemical and physical information in looking for approximate solutions of the Schrödinger equation are highlighted: model approximations and numerical approximations. Attention then turns to atomic orbitals as the basis of a description of molecular electronic structure; practical molecular wave functions; and a general strategy for performing molecular valence calculations. The final chapter examines the nature of the valence electronic structure by using invariance with respect to transformations among the occupied molecular orbitals and among the atomic orbitals. This text will be of interest to students and practitioners of chemistry, biochemistry, and quantum mechanics.
Download or read book Methods of Electronic Structure Theory written by Henry F. Schaefer and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: These two volumes deal with the quantum theory of the electronic structure of molecules. Implicit in the term ab initio is the notion that approximate solutions of Schrödinger's equation are sought "from the beginning," i. e. , without recourse to experimental data. From a more pragmatic viewpoint, the distin guishing feature of ab initio theory is usually the fact that no approximations are involved in the evaluation of the required molecular integrals. Consistent with current activity in the field, the first of these two volumes contains chapters dealing with methods per se, while the second concerns the application of these methods to problems of chemical interest. In asense, the motivation for these volumes has been the spectacular recent success of ab initio theory in resolving important chemical questions. However, these applications have only become possible through the less visible but equally important efforts of those develop ing new theoretical and computational methods and models. Henry F Schaefer Vll Contents Contents of Volume 4 XIX Chapter 1. Gaussian Basis Sets for Molecular Calculations Thom. H. Dunning, Ir. and P. Ieffrey Hay 1. Introduction . . . . . . . . . . . . . . . . 1 1. 1. Slater Functions and the Hydrogen Moleeule 1 1. 2. Gaussian Functions and the Hydrogen Atom 3 2. Hartree-Fock Calculations on the First Row Atoms 5 2. 1. Valence States of the First Row Atoms 6 7 2. 2. Rydberg States of the First Row Atoms 9 2. 3.
Download or read book Electronic Structure And Chemical Bonding written by Dunod Editeur and published by World Scientific. This book was released on 1996-09-20 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the problem of teaching the Electronic Structure and Chemical Bonding of atoms and molecules to high school and university students. It presents the outcomes of thorough investigations of some teaching methods as well as an unconventional didactical approach which were developed during a seminar for further training organized by the University of Bordeaux I for teachers of the physical sciences.The text is the result of a collective effort by eleven scientists and teachers: physicists and chemists doing research at the university or at the CRNS, university professors, and science teachers at high-school or university level.While remaining wide open to the latest discoveries of science, the text also offers a large number of problems along with their solutions and is illustrated by several pedagogic suggestions. It is intended for the use of teachers and students of physics, chemistry, and of the physical sciences in general.
Download or read book Calculation of Electronic Structure of Aluminum and Sodium Clusters Using the Method of Linear Combination of Atomic Orbitals written by Chao-Keng Chen and published by . This book was released on 1986 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enabling Electronic Structure Calculations of High Z Element Containing Materials Using Dirac Relativistic DFT Methods written by Patrick Ryan Thomas and published by . This book was released on 2020 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Novel properties may be induced in a host material by doping it with high Z elements to alter its underlying electronic states. Presently, no method exists that can accurately capture both large system sizes and the intricate fundamental physics of the induced multiplet states in the electronic structure. As part of a collaborative effort to merge a configuration interaction (CI) and density functional theory (DFT) method into one method that is capable of calculating the properties of high Z doped materials, an entirely new scheme for relativistic consideration of a localized orbital basis set and energy calculation was devised. This work presents a novel scheme for the creation of single-component scalar relativistic and four-component fully relativistic atomic orbital basis sets of Gaussian-type functions. A minimal norm least squares method was used to fit numerically represented, four-component Dirac spinors into a set of Gaussian basis functions possessing exponential coefficients expressed over a geometric series. A simultaneous parameter sweep of both the maximum range of exponential coefficients and number of terms in the expansion for each quantum number was used to optimize the basis set efficiency. An algorithm that circumvents the error prone direct calculation of relativistic kinetic energy terms has been adapted from the CI method of our collaborator into one compatible with the Orthogonalized Linear Combination of Atomic Orbitals DFT package. Lastly, an application of the current state-of-the-art in high-throughput relativistic DFT to a well-known material science problem will be discussed.
Download or read book Semiempirical Methods of Electronic Structure Calculation written by Gerald Segal and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: If one reflects upon the range of chemical problems accessible to the current quantum theoretical methods for calculations on the electronic structure of molecules, one is immediately struck by the rather narrow limits imposed by economic and numerical feasibility. Most of the systems with which experimental photochemists actually work are beyond the grasp of ab initio methods due to the presence of a few reasonably large aromatic ring systems. Potential energy surfaces for all but the smallest molecules are extremely expensive to produce, even over a restricted group of the possible degrees of freedom, and molecules containing the higher elements of the periodic table remain virtually untouched due to the large numbers of electrons involved. Almost the entire class of molecules of real biological interest is simply out of the question. In general, the theoretician is reduced to model systems of variable appositeness in most of these fields. The fundamental problem, from a basic computational point of view, is that large molecules require large numbers of basis functions, whether Slater type orbitals or Gaussian functions suitably contracted, to provide even a modestly accurate description of the molecular electronic environment. This leads to the necessity of dealing with very large matrices and numbers of integrals within the Hartree-Fock approximation and quickly becomes both numerically difficult and uneconomic.
Download or read book Electronic States of Molecules and Atom Clusters written by G. Del Re and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Orbital Approach to the Electronic Structure of Solids written by Enric Canadell and published by OUP Oxford. This book was released on 2012-01-12 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an intuitive yet sound understanding of how structure and properties of solids may be related. The natural link is provided by the band theory approach to the electronic structure of solids. The chemically insightful concept of orbital interaction and the essential machinery of band theory are used throughout the book to build links between the crystal and electronic structure of periodic systems. In such a way, it is shown how important tools for understanding properties of solids like the density of states, the Fermi surface etc. can be qualitatively sketched and used to either understand the results of quantitative calculations or to rationalize experimental observations. Extensive use of the orbital interaction approach appears to be a very efficient way of building bridges between physically and chemically based notions to understand the structure and properties of solids.
Download or read book Applications of Electronic Structure Theory written by Henry Schaefer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: These two volumes deal with the quantum theory of the electronic structure of ab initio is the notion that approximate solutions molecules. Implicit in the term of Schrodinger's equation are sought "from the beginning," i. e. , without recourse to experimental data. From a more pragmatic viewpoint, the distin guishing feature of ab initio theory is usually the fact that no approximations are involved in the evaluation of the required molecular integrals. Consistent with current activity in the field, the first of these two volumes contains chapters dealing with methods per se, while the second concerns the application of these methods to problems of chemical interest. In a sense, the motivation for these volumes has been the spectacular recent success of ab initio theory in resolving important chemical questions. However, these applications have only become possible through the less visible but equally important efforts of those developing new theoretical and computational methods and models. Henry F. Schaefer vii Contents Contents of Volume 3 xv Chapter 1. A Priori Geometry Predictions 1. A. Pople 1. Introduction . . . . . . . . . . . . . . . . . . . 1 2. Equilibrium Geometries by Hartree-Fock Theory 2 2. 1. Restricted and Unrestricted Hartree-Fock Theories 2 2. 2. Basis Sets for Hartree-Fock Studies . . . . . 4 2. 3. Hartree-Fock Structures for Small Molecules . 6 2. 4. Hartree-Fock Structures for Larger Molecules 12 3. Equilibrium Geometries with Correlation . . 18 4. Predictive Structures for Radicals and Cations 20 5. Conclusions 23 References 24 Chapter 2. Barriers to Rotation and Inversion Philip W. Payne and Leland C.
Download or read book ORBITAL THEORIES OF ELECTRONIC STRUCTURE written by WILLIAM H. ADAMS and published by . This book was released on 1962 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is shown that in the Hartree-Fock approximation there exists a uniquely defined Hermitian potential which describes the interaction of a model subgroup of electrons with the rest of the system. This potential can be divided into two parts. The first part is the difference between the Hartree-Fock Hamiltonian for the system and the model Hamiltonian. The second part is a nonlocal potential which cancels (screens) some of the first part. The essential point in the derivation is the choice of definition for model orbitals in the system. The only condition that must be satisfied by the occupied orbitals of the system is that they be linearly independent. It is also shown that there exist equations describing the best orbitals to use in a calculation by a linear combination of atomic orbitals method. They are the best orbitals to use because they give the exact answer. In order to link this method with others that have been described it is indicated how the pseudopotential form of the orthogonalized plane wave method may be derived. (Author).
Download or read book Semiempirical Methods of Electronic Structure Calculation written by Gerald Segal and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: If one reflects upon the range of chemical problems accessible to the current quantum theoretical methods for calculations on the electronic structure of molecules, one is immediately struck by the rather narrow limits imposed by economic and numerical feasibility. Most of the systems with which experimental photochemists actually work are beyond the grasp of ab initio methods due to the presence of a few reasonably large aromatic ring systems. Potential energy surfaces for all but the smallest molecules are extremely expensive to produce, even over a restricted group of the possible degrees of freedom, and molecules containing the higher elements of the periodic table remain virtually untouched due to the large numbers of electrons involved. Almost the entire class of molecules of real biological interest is simply out of the question. In general, the theoretician is reduced to model systems of variable appositeness in most of these fields. The fundamental problem, from a basic computational point of view, is that large molecules require large numbers of basis functions, whether Slater type orbitals or Gaussian functions suitably contracted, to provide even a modestly accurate description of the molecular electronic environment. This leads to the necessity of dealing with very large matrices and numbers of integrals within the Hartree-Fock approximation and quickly becomes both numerically difficult and uneconomic.
Download or read book Electronic Structure written by Richard M. Martin and published by Cambridge University Press. This book was released on 2020-08-27 with total page 791 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of electronic structure of materials is at a momentous stage, with new computational methods and advances in basic theory. Many properties of materials can be determined from the fundamental equations, and electronic structure theory is now an integral part of research in physics, chemistry, materials science and other fields. This book provides a unified exposition of the theory and methods, with emphasis on understanding each essential component. New in the second edition are recent advances in density functional theory, an introduction to Berry phases and topological insulators explained in terms of elementary band theory, and many new examples of applications. Graduate students and research scientists will find careful explanations with references to original papers, pertinent reviews, and accessible books. Each chapter includes a short list of the most relevant works and exercises that reveal salient points and challenge the reader.
Download or read book The Electronic Structure of Complex Systems written by P. Phariseau and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 807 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Structures and Approximations for Electrons in Molecules written by David B. Cook and published by Ellis Horwood. This book was released on 1978 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
