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 Relativistic Electronic Structure Theory written by and published by Elsevier. This book was released on 2004-03-05 with total page 805 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of relativistic electronic structure theory is generally not part of theoretical chemistry education, and is therefore not covered in most quantum chemistry textbooks. This is due to the fact that only in the last two decades have we learned about the importance of relativistic effects in the chemistry of heavy and superheavy elements. Developments in computer hardware together with sophisticated computer algorithms make it now possible to perform four-component relativistic calculations for larger molecules. Two-component and scalar all-electron relativistic schemes are also becoming part of standard ab-initio and density functional program packages for molecules and the solid state. The second volume of this two-part book series is therefore devoted to applications in this area of quantum chemistry and physics of atoms, molecules and the solid state. Part 1 was devoted to fundamental aspects of relativistic electronic structure theory whereas Part 2 covers more of the applications side. This volume opens with a section on the Chemistry of the Superheavy Elements and contains chapters dealing with Accurate Relativistic Fock-Space Calculations for Many-Electron Atoms, Accurate Relativistic Calculations Including QED, Parity-Violation Effects in Molecules, Accurate Determination of Electric Field Gradients for Heavy Atoms and Molecules, Two-Component Relativistic Effective Core Potential Calculations for Molecules, Relativistic Ab-Initio Model Potential Calculations for Molecules and Embedded Clusters, Relativistic Pseudopotential Calculations for Electronic Excited States, Relativistic Effects on NMR Chemical Shifts, Relativistic Density Functional Calculations on Small Molecules, Quantum Chemistry with the Douglas-Kroll-Hess Approach to Relativistic Density Functional Theory, and Relativistic Solid State Calculations. - Comprehensive publication which focuses on new developments in relativistic quantum electronic structure theory- Many leaders from the field of theoretical chemistry have contributed to the TCC series- Will no doubt become a standard text for scientists in this field.
Download or read book Reliable Electronic Structure Calculations for Heavy Element Chemistry written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It is now possible to calculate many properties including the energetics (total bond dissociation energies or heats of formation) of molecules containing light elements to high accuracy by using correlation-consistent basis sets, coupled cluster theory and including additive corrections for core-valence and relativistic effects and careful treatment of the zero point energy. We propose to develop software for ab initio electronic structure calculations based on molecular orbital theory and density functional theory with the proper treatment of relativistic effects to study complexes of heavy elements in order to assist in understanding and predicting the chemistry of the actinides, lanthanides, and heavy transition metals, molecules critical to DOE missions including environmental management. The proposed work will focus on the development of these electronic structure methods and their implementation in software on advanced massively parallel processor (MPP) computer architectures capable of multi-tens of teraflops to petaflops. The core of the software will be developed within the NWChem and Columbus software suites. We propose to make the software broadly available so that other scientists can use these tools to address the complex environmental problems facing the Department of Energy's nuclear production sites as well as other waste sites in the Nation. Our implementation of relativistic quantum chemical methods for massively parallel computers will enable us to simulate the behavior of heavy-element compounds at the same type of level currently available for light-element compounds. In addition, this work will enable us to provide better methods for benchmarks of the additive energetic schemes currently available for light atom compounds. The theoretical and computational methodology so developed will be an invaluable supplement to current, very expensive experimental studies of the actinides, lanthanides, and radioactive heavy transition metal elements, allowing limited experimental data to be extrapolated to many other regimes of interest. The program objectives will be attained through a multi-site collaboration from PNNL, Ohio State University, University of Memphis and Eloret that includes leading researchers in the areas of high-performance computational chemistry and relativistic theoretical chemistry. The new tools can be used to study, for example, the interaction of actinides with organic complexing agents present in tank wastes and with natural aqueous systems (carbonates) in order to better understand their fate and transport in the environment, as well as interactions with new materials such as phosphates and amides for the design of innovative in situ remediation technologies and separation materials. In addition, the proposed work will allow scientists to tackle the complexity of excited states in heavy element compounds especially those comprised of actinide, lanthanide, and heavy transition metal atoms.
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 The Dirac Equation in Electronic Structure Calculations written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Brooks, Johansson, and Skriver, using the LMTO-ASA method and considerable insight, were able to explain many of the ground state properties of the actinides. In the many years since this work was done, electronic structure calculations of increasing sophistication have been applied to actinide elements and compounds, attempting to quantify the applicability of DFT to actinides and actinide compounds and to try to incorporate other methodologies (i.e. DMFT) into DFT calculations. Through these calculations, the limits of both available density functionals and ad hoc methodologies are starting to become clear. However, it has also become clear that approximations used to incorporate relativity are not adequate to provide rigorous tests of the underlying equations of DFT, not to mention ad hoc additions. In this talk, we describe the result of full-potential LMTO calculations for the elemental actinides, comparing results obtained with a full Dirac basis with those obtained from scalar-relativistic bases, with and without variational spin-orbit. This comparison shows that the scalar relativistic treatment of actinides does not have sufficient accuracy to provide a rigorous test of theory and that variational spin-orbit introduces uncontrolled errors in the results of electronic structure calculations on actinide elements.
Download or read book Theoretical Chemistry and Physics of Heavy and Superheavy Elements written by U. Kaldor and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum mechanics provides the fundamental theoretical apparatus for describing the structure and properties of atoms and molecules in terms of the behaviour of their fundamental components, electrons and nudeL For heavy atoms and molecules containing them, the electrons can move at speeds which represent a substantial fraction of the speed of light, and thus relativity must be taken into account. Relativistic quantum mechanics therefore provides the basic formalism for calculating the properties of heavy-atom systems. The purpose of this book is to provide a detailed description of the application of relativistic quantum mechanics to the many-body prob lem in the theoretical chemistry and physics of heavy and superheavy elements. Recent years have witnessed a continued and growing interest in relativistic quantum chemical methods and the associated computa tional algorithms which facilitate their application. This interest is fu elled by the need to develop robust, yet efficient theoretical approaches, together with efficient algorithms, which can be applied to atoms in the lower part of the Periodic Table and, more particularly, molecules and molecular entities containing such atoms. Such relativistic theories and computational algorithms are an essential ingredient for the description of heavy element chemistry, becoming even more important in the case of superheavy elements. They are destined to become an indispensable tool in the quantum chemist's armoury. Indeed, since relativity influences the structure of every atom in the Periodic Table, relativistic molecular structure methods may replace in many applications the non-relativistic techniques widely used in contemporary research.
Download or read book Density Functional Theory written by David S. Sholl and published by John Wiley & Sons. This book was released on 2011-09-20 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Demonstrates how anyone in math, science, and engineering can master DFT calculations Density functional theory (DFT) is one of the most frequently used computational tools for studying and predicting the properties of isolated molecules, bulk solids, and material interfaces, including surfaces. Although the theoretical underpinnings of DFT are quite complicated, this book demonstrates that the basic concepts underlying the calculations are simple enough to be understood by anyone with a background in chemistry, physics, engineering, or mathematics. The authors show how the widespread availability of powerful DFT codes makes it possible for students and researchers to apply this important computational technique to a broad range of fundamental and applied problems. Density Functional Theory: A Practical Introduction offers a concise, easy-to-follow introduction to the key concepts and practical applications of DFT, focusing on plane-wave DFT. The authors have many years of experience introducing DFT to students from a variety of backgrounds. The book therefore offers several features that have proven to be helpful in enabling students to master the subject, including: Problem sets in each chapter that give readers the opportunity to test their knowledge by performing their own calculations Worked examples that demonstrate how DFT calculations are used to solve real-world problems Further readings listed in each chapter enabling readers to investigate specific topics in greater depth This text is written at a level suitable for individuals from a variety of scientific, mathematical, and engineering backgrounds. No previous experience working with DFT calculations is needed.
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 Density Functional Theory in Quantum Chemistry written by Takao Tsuneda and published by Springer Science & Business Media. This book was released on 2014-02-18 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, density functional theory (DFT) is introduced within the overall context of quantum chemistry. DFT has become the most frequently used theory in quantum chemistry calculations. However, thus far, there has been no book on the fundamentals of DFT that uses the terminology and methodology of quantum chemistry, which is familiar to many chemists, including experimentalists. This book first reviews the basic concepts and historical background of quantum chemistry and then explains those of DFT, showing how the latter fits into the bigger picture. Recent interesting topics of DFT in chemistry are also targeted. In particular, the physical meanings of state-of-the-art exchange-correlation functionals and their corrections are described in detail. Owing to its unconventionality, this book is certain to be of great interest not only to chemists but also to solid state physicists.
Download or read book Ideas of Quantum Chemistry written by Lucjan Piela and published by Elsevier. This book was released on 2006-11-28 with total page 1122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ideas of Quantum Chemistry shows how quantum mechanics is applied to chemistry to give it a theoretical foundation. The structure of the book (a TREE-form) emphasizes the logical relationships between various topics, facts and methods. It shows the reader which parts of the text are needed for understanding specific aspects of the subject matter. Interspersed throughout the text are short biographies of key scientists and their contributions to the development of the field.Ideas of Quantum Chemistry has both textbook and reference work aspects. Like a textbook, the material is organized into digestable sections with each chapter following the same structure. It answers frequently asked questions and highlights the most important conclusions and the essential mathematical formulae in the text. In its reference aspects, it has a broader range than traditional quantum chemistry books and reviews virtually all of the pertinent literature. It is useful both for beginners as well as specialists in advanced topics of quantum chemistry. The book is supplemented by an appendix on the Internet. * Presents the widest range of quantum chemical problems covered in one book * Unique structure allows material to be tailored to the specific needs of the reader * Informal language facilitates the understanding of difficult topics
Download or read book Relativistic Quantum Chemistry written by Markus Reiher and published by John Wiley & Sons. This book was released on 2009-05-13 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by two researchers in the field, this book is a reference to explain the principles and fundamentals in a self-contained, complete and consistent way. Much attention is paid to the didactical value, with the chapters interconnected and based on each other. From the contents: * Fundamentals * Relativistic Theory of a Free Electron: Diracï¿1⁄2s Equation * Dirac Theory of a Single Electron in a Central Potential * Many-Electron Theory I: Quantum Electrodynamics * Many-Electron Theory II: Dirac-Hartree-Fock Theory * Elimination of the Small Component * Unitary Transformation Schemes * Relativistic Density Functional Theory * Physical Observables and Molecular Properties * Interpretive Approach to Relativistic Quantum Chemistry From beginning to end, the authors deduce all the concepts and rules, such that readers are able to understand the fundamentals and principles behind the theory. Essential reading for theoretical chemists and physicists.
Download or read book Computational Quantum Chemistry written by Masoud Soroush and published by Elsevier. This book was released on 2018-10-16 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Quantum Chemistry: Insights into Polymerization Reactions consolidates extensive research results, couples them with computational quantum chemistry (CQC) methods applicable to polymerization reactions, and presents those results systematically. CQC has advanced polymer reaction engineering considerably for the past two decades. The book puts these advances into perspective. It also allows you to access the most up-to-date research and CQC methods applicable to polymerization reactions in a single volume. The content is rigorous yet accessible to graduate students as well as researchers who need a reference of state-of-the-art CQC methods with polymerization applications. Consolidates more than 10 years of theoretical polymerization reaction research currently scattered across journal articles Accessibly presents CQC methods applicable to polymerization reactions Provides researchers with a one-stop source of the latest theoretical developments in polymer reaction engineering
Download or read book Single site Green Function of the Dirac Equation for Full potential Electron Scattering written by Pascal Kordt and published by Forschungszentrum Jülich. This book was released on 2012 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Relativistic Quantum Chemistry written by Kenneth G. Dyall and published by Oxford University Press. This book was released on 2007-04-19 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an introduction to the essentials of relativistic effects in quantum chemistry, and a reference work that collects all the major developments in this field. It is designed for the graduate student and the computational chemist with a good background in nonrelativistic theory. In addition to explaining the necessary theory in detail, at a level that the non-expert and the student should readily be able to follow, the book discusses the implementation of the theory and practicalities of its use in calculations. After a brief introduction to classical relativity and electromagnetism, the Dirac equation is presented, and its symmetry, atomic solutions, and interpretation are explored. Four-component molecular methods are then developed: self-consistent field theory and the use of basis sets, double-group and time-reversal symmetry, correlation methods, molecular properties, and an overview of relativistic density functional theory. The emphases in this section are on the basics of relativistic theory and how relativistic theory differs from nonrelativistic theory. Approximate methods are treated next, starting with spin separation in the Dirac equation, and proceeding to the Foldy-Wouthuysen, Douglas-Kroll, and related transformations, Breit-Pauli and direct perturbation theory, regular approximations, matrix approximations, and pseudopotential and model potential methods. For each of these approximations, one-electron operators and many-electron methods are developed, spin-free and spin-orbit operators are presented, and the calculation of electric and magnetic properties is discussed. The treatment of spin-orbit effects with correlation rounds off the presentation of approximate methods. The book concludes with a discussion of the qualitative changes in the picture of structure and bonding that arise from the inclusion of relativity.
Download or read book Electronic Structure of Quantum Confined Atoms and Molecules written by K.D. Sen and published by Springer. This book was released on 2014-09-19 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present volume is a collection of review articles highlighting the fundamental advances made in this area by the internationally acclaimed research groups , most of them being pioneers themselves and coming together for the first time.
Download or read book Organic Conductors written by Jean-Pierre Farges and published by CRC Press. This book was released on 2022-09-16 with total page 874 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work examines all aspects of organic conductors, detailing recent theoretical concepts and current laboratory methods of synthesis, measurement, control and analysis. It describes advances in molecular-scale engineering, including switching and memory systems, Schottky and electroluminescent diodes, field-effect transistors, and photovoltaic devices and solar cells.
Download or read book Density Functional Theory of Atoms and Molecules written by Robert G. Parr and published by Oxford University Press. This book was released on 1994-05-26 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a rigorous, unified account of the fundamental principles of the density-functional theory of the electronic structure of matter and its applications to atoms and molecules. Containing a detailed discussion of the chemical potential and its derivatives, it provides an understanding of the concepts of electronegativity, hardness and softness, and chemical reactivity. Both the Hohenberg-Kohn-Sham and the Levy-Lieb derivations of the basic theorems are presented, and extensive references to the literature are included. Two introductory chapters and several appendices provide all the background material necessary beyond a knowledge of elementary quantum theory. The book is intended for physicists, chemists, and advanced students in chemistry.
