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Author: Petr Carsky Publisher: Springer Science & Business Media ISBN: 3642931405 Category : Science Languages : en Pages : 256
Book Description
Until recently quantum chemical ab initio calculations were re stricted to atoms and very small molecules. As late as in 1960 Allen l and Karo stated : "Almost all of our ab initio experience derives from diatomic LCAO calculations ••• N and we have found in the litera ture "approximately eighty calculations, three-fourths of which are for diatomic molecules ••• There are approximately twenty ab initio calculations for molecules with more than two atoms, but there is a decided dividing line between the existing diatomic and polyatomic wave functions. Confidence in the satisfactory evaluation of the many -center two-electron integrals is very much less than for the diatom ic case". Among the noted twenty calculations, SiH was the largest 4 molecule treated. In most cases a minimal basis set was used and the many-center two-electron integrals were calculated in an approximate way. Under these circumstances the ab initio calculations could hard ly provide useful chemical information. It is therefore no wonder that the dominating role in the field of chemical applications was played by semiempirical and empirical methods. The situation changed essentially in the next decade. The problem of many-center integrals was solved, efficient and sophisticated computer programs were devel oped, basis sets suitable for a given type of problem were suggested, and, meanwhile, a considerable amount of results has been accumulated which serve as a valuable comparative material. The progress was of course inseparable from the development and availability of computers.
Author: Christopher J. Cramer Publisher: Springer ISBN: 9783642442490 Category : Science Languages : en Pages : 0
Book Description
On the occasion of the 50th anniversary of the journal Theoretical Chemistry Accounts, leading researchers in theoretical chemistry present current and forward-looking perspectives on major developments in the field. Originally published in the journal, these outstanding contributions are now available in a hardcover print format. This collection will be of benefit in particular to those research groups and libraries that have chosen to have only electronic access to the journal. With contributions from Christopher J. Cramer, Gino A. DiLabio, Filipp Furche, Sophya Garashchuk, Peter M.W. Gill, Hua Guo, So Hirata, Brian K. Kendrick, Hans Lischka, Wenjian Liu, Fernando R. Ornellas, Irina Paci, Kirk A. Peterson, Markus Reiher, Jeffrey R. Reimers, Manuel Smeu, Seiichiro Ten-no, Diego Troya, Donald G. Truhlar, Christoph van Wüllen, Dong H. Zhang
Author: S. G. Christov Publisher: Springer Science & Business Media ISBN: 3642931421 Category : Science Languages : en Pages : 336
Book Description
Since the discovery of quantum mechanics,more than fifty years ago,the theory of chemical reactivity has taken the first steps of its development. The knowledge of the electronic structure and the properties of atoms and molecules is the basis for an un derstanding of their interactions in the elementary act of any chemical process. The increasing information in this field during the last decades has stimulated the elaboration of the methods for evaluating the potential energy of the reacting systems as well as the creation of new methods for calculation of reaction probabili ties (or cross sections) and rate constants. An exact solution to these fundamental problems of theoretical chemistry based on quan tum mechanics and statistical physics, however, is still impossible even for the simplest chemical reactions. Therefore,different ap proximations have to be used in order to simplify one or the other side of the problem. At present, the basic approach in the theory of chemical reactivity consists in separating the motions of electrons and nu clei by making use of the Born-Oppenheimer adiabatic approximation to obtain electronic energy as an effective potential for nuclear motion. If the potential energy surface is known, one can calculate, in principle, the reaction probability for any given initial state of the system. The reaction rate is then obtained as an average of the reaction probabilities over all possible initial states of the reacting ~artic1es. In the different stages of this calculational scheme additional approximations are usually introduced.
Author: P. Arrighini Publisher: Springer Science & Business Media ISBN: 3642931820 Category : Science Languages : en Pages : 254
Book Description
The aim of these notes is to offer a modern picture of the pertur bative approach to the calculation of intermolecular forces. The point of view taken is that a perturbative series truncated at a low order can provide a valuable way for ~valuating interaction energies, especial ly if one limits oneself to the case of intermediate- and long-range distances between the interacting partners. Although the situation corresponding to short distances is essen tially left out from our presentation, the problems which are within the range of the theory form a vast and important class: a large var iety of phenomena of matter, in fact, depends on the existence of in teractions among atoms or molecules, which over a substantial range of distances should be classified as weak in comparison to the interactions occurring inside atoms or molecules. We are aware of the omission of some topics, which in principle could have been included in our review. For instance, a very scarce at tention has been paid to the analysis of problems involving interacting partners in degenerate states, which is of particular relevance in the case of interactions between excited atoms (only a rather quick presen tation of the formal apparatus of degenerate perturbation theory is in cluded in Chap. III). Interactions involving the simultaneous presence of more than two atoms (or mOlecules) have not been considered, with the consequent non-necessity of considering nonadditive effects which characterize the general N-body problem.
Author: Piet W.N.M. van Leeuwen Publisher: Springer Science & Business Media ISBN: 9401104751 Category : Science Languages : en Pages : 219
Book Description
This publication is the first to present the quantitative application of quantum chemistry to organometallic reactions. Great progress has been made in recent years in the calculation of transition states of organometallic conversions in both homo and heterogeneous catalysis. This volume, which contains seven contributions by leading scientists, deals with key reactions of homogeneous catalysis including oxidative addition, migratory insertions, 2+2 additions, the Wacker reaction, and epoxidation. The book provides experimental chemists with an up-to-date overview of the state of the art in this field, and will stimulate an adjustment of views previously based on semiempirical calculations. For researchers and advanced graduate students whose work involves organometallics and catalysis.
Author: Christopher Cramer Publisher: Springer Science & Business Media ISBN: 3662104210 Category : Science Languages : en Pages : 205
Book Description
For the New Century Issue of the journal "Theroretical Chemistry Accounts" the advisory editors identified papers from the first century of theoretical chemistry and discussed their importance for the twentieth century with an eye towards the twenty-first century. Sixty-six such perspectives are published in the New Century Issue. To make this unique collection available to younger scientists for entertaining reading and re-reading of the original publications, the publisher decided to reprint a special edition of the issue.
Author: J.-M. André Publisher: Springer Science & Business Media ISBN: 9400998120 Category : Technology & Engineering Languages : en Pages : 381
Book Description
The NATO Advanced Study Institute on "Electronic Structure and Properties of Polymers" was held at the Facultes Universitaires de Namur (F.U.N.) from August 31 till September 14, 1977. We wish to express our deepest gratitude to the Scientific Affairs Division of NATO, the main sponsor of this Institute, and to the Facultes Universitaires Notre Dame de la Paix and their Board who gave us generous financial help as well as accommodation for the School. Our sincere thanks to Dr Tilo Kester from the NATO Scien tific Affairs Division and Prof. Roger Troisfontaines, Rector and President ~f the Facultes Notre Dame de la Paix. This volume contains the main lectures of the Institute. It is our great pleasure to thank all the lecturers for their most excellent and interesting lectures and for the clarity of their manuscripts. During the School the participants and lecturers felt that though there has been considerable progress in recent years in the methods applicable to the quantum theoretical treatment of polymers, not very many calculations of their properties have been performed. This is the reason that the title of this volume has been changed to "Quantum Theory of Polymers".
Author: Jacek Wojcik Publisher: Royal Society of Chemistry ISBN: 1849735778 Category : Medical Languages : en Pages : 593
Book Description
Applications of Nuclear Magnetic Resonance (NMR) span a wide range of scientific disciplines, including physis, biology and medicine. Each volume in this series comprises a combination of reports offering a comprehensive coverage of the literature. With an unrivalled scope of coverage, this Specialist Periodical Report presents an invaluable source of current methods and applications for seasoned practitioners and newcomers alike.
Author: Frederick E. Wang Publisher: Elsevier ISBN: 0080459730 Category : Technology & Engineering Languages : en Pages : 219
Book Description
Bonding Theory for Metals and Alloys exhorts the potential existence of covalent bonding in metals and alloys. Through the recognition of the covalent bond in coexistence with the 'free' electron band, the book describes and demonstrates how the many experimental observations on metals and alloys can all be reconciled. Subsequently, it shows how the individual view of metals and alloys by physicists, chemists and metallurgists can be unified. The physical phenomena of metals and alloys covered in this book are: Miscibility Gap between two liquid metals; Phase Equilibrium Diagrams; Phenomenon of Melting. Superconductivity; Nitinol; A Metal-Alloy with Memory; Mechanical Properties; Liquid Metal Embrittlement; Superplasticity; Corrosion; The author introduces a new theory based on 'Covalon' conduction, which forms the basis for a new approach to the theory of superconductivity. This new approach not only explains the many observations made on the phenomenon of superconductivity but also makes predictions that have been confirmed.* Openly recognizes the electrons as the most important and the only factor in understanding metals and alloys* Proposes "Covalon" conduction theory, which carries current in covalent bonded pairs* Investigates phase diagrams both from theoretical and experimental point of view
Author: Petr Carsky Publisher: Springer Science & Business Media ISBN: 3642931405 Category : Science Languages : en Pages : 256
Book Description
Until recently quantum chemical ab initio calculations were re stricted to atoms and very small molecules. As late as in 1960 Allen l and Karo stated : "Almost all of our ab initio experience derives from diatomic LCAO calculations ••• N and we have found in the litera ture "approximately eighty calculations, three-fourths of which are for diatomic molecules ••• There are approximately twenty ab initio calculations for molecules with more than two atoms, but there is a decided dividing line between the existing diatomic and polyatomic wave functions. Confidence in the satisfactory evaluation of the many -center two-electron integrals is very much less than for the diatom ic case". Among the noted twenty calculations, SiH was the largest 4 molecule treated. In most cases a minimal basis set was used and the many-center two-electron integrals were calculated in an approximate way. Under these circumstances the ab initio calculations could hard ly provide useful chemical information. It is therefore no wonder that the dominating role in the field of chemical applications was played by semiempirical and empirical methods. The situation changed essentially in the next decade. The problem of many-center integrals was solved, efficient and sophisticated computer programs were devel oped, basis sets suitable for a given type of problem were suggested, and, meanwhile, a considerable amount of results has been accumulated which serve as a valuable comparative material. The progress was of course inseparable from the development and availability of computers.
Author: Howard Maskill Publisher: John Wiley & Sons ISBN: 0470994169 Category : Science Languages : en Pages : 392
Book Description
A range of alternative mechanisms can usually be postulated for most organic chemical reactions, and identification of the most likely requires detailed investigation. Investigation of Organic Reactions and their Mechanisms will serve as a guide for the trained chemist who needs to characterise an organic chemical reaction and investigate its mechanism, but who is not an expert in physical organic chemistry. Such an investigation will lead to an understanding of which bonds are broken, which are made, and the order in which these processes happen. This information and knowledge of the associated kinetic and thermodynamic parameters are central to the development of safe, efficient, and profitable industrial chemical processes, and to extending the synthetic utility of new chemical reactions in chemical and pharmaceutical manufacturing, and academic environments. Written as a coherent account of the principal methods currently used in mechanistic investigations, at a level accessible to academic researchers and graduate chemists in industry, the book is highly practical in approach. The contributing authors, an international group of expert practitioners of the techniques covered, illustrate their contributions by examples from their own research and from the relevant wider chemical literature. The book covers basic aspects such as product analysis, kinetics, catalysis, and investigation of reactive intermediates. It also includes material on significant recent developments, e.g. computational chemistry, calorimetry, and electrochemistry, in addition to topics of high current industrial relevance, e.g. reactions in multiphase systems, and synthetically useful reactions involving free radicals and catalysis by organometallic compounds.
Author: Petr Carsky
Author: Christopher J. Cramer
Author: S. G. Christov
Author: P. Arrighini
Author: Piet W.N.M. van Leeuwen
Author: Christopher Cramer
Author: J.-M. André
Author: Jacek Wojcik
Author: Frederick E. Wang
Author: Petr Carsky
Author: Howard Maskill