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 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 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 Dynamics of Molecular Collisions written by W. Miller and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Activity in any theoretical area is usually stimulated by new experimental techniques and the resulting opportunity of measuring phenomena that were previously inaccessible. Such has been the case in the area under consideration he re beginning about fifteen years aga when the possibility of studying chemical reactions in crossed molecular beams captured the imagination of physical chemists, for one could imagine investigating chemical kinetics at the same level of molecular detail that had previously been possible only in spectroscopic investigations of molecular stucture. This created an interest among chemists in scattering theory, the molecular level description of a bimolecular collision process. Many other new and also powerful experimental techniques have evolved to supplement the molecular be am method, and the resulting wealth of new information about chemical dynamics has generated the present intense activity in molecular collision theory. During the early years when chemists were first becoming acquainted with scattering theory, it was mainly a matter of reading the physics literature because scattering experiments have long been the staple of that field. It was natural to apply the approximations and models that had been developed for nuclear and elementary particle physics, and although some of them were useful in describing molecular collision phenomena, many were not.

Download or read book Statistical Mechanics written by Bruce Berne and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last decade has been marked by a rapid growth in statistical mechanics, especially in connection with the physics and chemistry of the fluid state. Our understanding in these areas has been considerably advanced and enriched by the discovery of new techniques and the sharpening of old techniques, ranging all the way from computer simulation to mode-mode coupling theories. Statistical mechanics brings together under one roof a broad spectrum of mathematical techniques. The aim of these volumes is to provide a didactic treatment of those techniques that are most useful for the study of problems of current interest to theoretical chemists. The emphasis throughout is on the techniques themselves and not on reviewing the enormous literature in statistical mechanics. Each author was charged with the following task. Given N pages, (a) pose the problem, (b) present those aspects of the particular technique that clearly illustrate its internal workings, (c) apply the technique to the solution of several illustrative examples, and (d) write the chapter so that it will enable the reader to approach key citations to the literature intelligently. These volumes are designed for graduate students and research workers in statistical mechanics. Nevertheless, because of the range of techniques and their general utility, they should be useful in other areas as well.

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 1989-04-13 with total page 343 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.

Download or read book Molecular Orbitals and their Energies Studied by the Semiempirical HAM Method written by Einar Lindholm and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: This treatment of molecular and atomic physics is primarily meant as a textbook. It is intended for both chemists and physicists. ·It can be read without much knowledge of quantum mechanics or mathematics, since all such details are explained-. It has developed through a series of lectures at the Royal Institute of Technology. The content is to about 50 % theoretical and to 50 % experimental. The reason why the authors, who are experimentalists, went into theory is the following. When we during the beginning of the 1970's measured photo electron spectra of organic molecules, it appeared to be impossible to understand them by use of available theoretical calculations. To handle hydrocarbons we ( together with C. Fridh ) constructed in 1972 a purely empirical procedure, SPINDO [1] which has proved to be useful, but the extension to molecules with hetero atoms appeared to be difficult. One of us ( L.A.) proposed then another purely ~~E!E!~~! EE2~~~~E~ ( Hydrogenic Atoms in Molecules, HAM/1, unpublished), in which the Fock matrix elements f5..y were parametrized using Slater's shielding concept. The self-repulsion was compensated by a term "-1". The §~~2~~_~ff2E~, HAM/2 [2] , started from the total energy E:. of the molecule. The atomic parts of L used the Slater shielding constants, and the bond parts of E. were taken from SPINDO. The Fock matrix elements Fpv were then obtained from E in a conventional way.

Download or read book Quantum Chemistry of Organic Compounds written by Vladimir I. Minkin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemistry is the science of substances (today we would say molecules) and their transformations. Central to this science is the complexity of shape and function of its typical representatives. There lies, no longer dependent on its vitalistic antecedents, the rich realm of molecular possibility called organic chemistry. In this century we have learned how to determine the three-dimensional structure of molecules. Now chemistry as whole, and organic chemistry in particular, is poised to move to the exploration of its dynamic dimension, the busy business of transformations or reactions. Oh, it has been done all along, for what else is synthesis? What I mean is that the theoretical framework accom panying organic chemistry, long and fruitfully laboring on a quantum chemical understanding of structure, is now making the first tentative motions toward building an organic theory of reactivity. The Minkin, Simkin, Minyaev book takes us in that direction. It incorporates the lessons of frontier orbital theory and of Hartree-Fock SCF calculations; what chemical physicists have learned about trajectory calculations of selected reactions, and a simplified treatment of all-important solvent effects. It is written by professional, accomplished organic chemists for other organic chemists; it is consistently even-toned in its presentation of contending approaches. And very much up to date. That this contemporary work should emerge from a regional university in a country in which science has been highly centralized and organic chemistry not very modern, invites reflection.

Download or read book Theoretical Treatment of Large Molecules and Their Interactions written by Zvonimir B. Maksic and published by Springer Science & Business Media. This book was released on 2013-03-07 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: The French chemist Marcelin Berthelot put forward a classical and by now an often cited sentence revealing the quintessence of the chemical science: "La Chimie cree son objet". This is certainly true because the largest number of molecular compounds were and are continuously synthesized by chemists themselves. However, modern computational quantum chemistry has reached a state of maturity that one can safely say: "La Chimie Theorique cree son objet" as well. Indeed, modern theoretical chemistry is able today to provide reliable results on elusive systems such as short living species, reactive intermediates and molecules which will perhaps never be synthesized because of one or another type of instability. It is capable of yielding precious information on the nature of the transition states, reaction paths etc. Additionally, computational chemistry gives some details of the electronic and geometric structure of molecules which remain hidden in experimental examinations. Hence, it follows that powerful numerical techniques have substantially enlarged the domain of classical chemistry. On the other hand, interpretive quantum chemistry has provided a conceptual framework which enabled rationalization and understanding of the precise data offered either by experiment or theory. It is modelling which gives a penetrating insight into the chemical phenomena and provides order in raw experimental results which would otherwise represent just a large catalogue of unrelated facts.

Download or read book Calculation of NMR and EPR Parameters written by Martin Kaupp and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 621 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book to present the necessary quantum chemical methods for both resonance types in one handy volume, emphasizing the crucial interrelation between NMR and EPR parameters from a computational and theoretical point of view. Here, readers are given a broad overview of all the pertinent topics, such as basic theory, methodic considerations, benchmark results and applications for both spectroscopy methods in such fields as biochemistry, bioinorganic chemistry as well as with different substance classes, including fullerenes, zeolites and transition metal compounds. The chapters have been written by leading experts in a given area, but with a wider audience in mind. The result is the standard reference on the topic, serving as a guide to the best computational methods for any given problem, and is thus an indispensable tool for scientists using quantum chemical calculations of NMR and EPR parameters. A must-have for all chemists, physicists, biologists and materials scientists who wish to augment their research by quantum chemical calculations of magnetic resonance data, but who are not necessarily specialists in these methods or their applications. Furthermore, specialists in one of the subdomains of this wide field will be grateful to find here an overview of what lies beyond their own area of focus.

Download or read book Computational Medicinal Chemistry for Drug Discovery written by Patrick Bultinck and published by CRC Press. This book was released on 2003-12-17 with total page 829 pages. Available in PDF, EPUB and Kindle. Book excerpt: Observing computational chemistry's proven value to the introduction of new medicines, this reference offers the techniques most frequently utilized by industry and academia for ligand design. Featuring contributions from more than fifty pre-eminent scientists, Computational Medicinal Chemistry for Drug Discovery surveys molecular structure computation, intermolecular behavior, ligand-receptor interaction, and modeling responding to market demands in its selection and authoritative treatment of topics. The book examines molecular mechanics, semi-empirical methods, wave function-based quantum chemistry, density functional theory, 3-D structure generation, and hybrid methods.

Download or read book Polyatomic Molecules written by Robert S. Mulliken and published by Elsevier. This book was released on 2012-12-02 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polyatomic Molecules: Results of Ab Initio Calculations describes the symmetry of polyatomic molecules in ground states. This book contains 12 chapters that also cover the excited and ionized states of these molecules. The opening chapter describes the nature of the various ab initio computational methods. The subsequent four chapters deal with the three-atom systems, differing with respect to the number of hydrogen atoms in the molecules. These chapters also discuss the reaction surfaces of these systems. These topics are followed by discussions on the molecules whose ground states belong to relatively high, little or no symmetry groups. The concluding chapters explore the inorganic and relatively large organic molecules. These chapters also examine the ab initio calculations of molecular compounds and complexes, as well as hydrogen bonding and ion hydration. This text will be of great value to organic and inorganic chemists and physicists.

Download or read book Reviews in Computational Chemistry Volume 23 written by Kenny B. Lipkowitz and published by John Wiley & Sons. This book was released on 2007-02-26 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: THIS VOLUME, LIKE THOSE PRIOR TO IT, FEATURES CHAPTERS BY EXPERTS IN VARIOUS FIELDS OF COMPUTATIONAL CHEMISTRY. Volume 23 COVERS LINEAR SCALING METHODS FOR QUANTUM CHEMISTRY, VARIATIONAL TRANSITION STATE THEORY, COARSE GRAIN MODELING OF POLYMERS, SUPPORT VECTOR MACHINES, CONICAL INTERSECTIONS, ANALYSIS OF INFORMATION CONTENT USING SHANNON ENTROPY, AND HISTORICAL INSIGHTS INTO HOW COMPUTING EVOLVED IN THE PHARMACEUTICAL INDUSTRY. FROM REVIEWS OF THE SERIES "Reviews in Computational Chemistry remains the most valuable reference to methods and techniques in computational chemistry." —JOURNAL OF MOLECULAR GRAPHICS AND MODELLING "One cannot generally do better than to try to find an appropriate article in the highly successful Reviews in Computational Chemistry. The basic philosophy of the editors seems to be to help the authors produce chapters that are complete, accurate, clear, and accessible to experimentalists (in particular) and other nonspecialists (in general)." —JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Download or read book Progress in Chemometrics Research written by Alexey L. Pomerantsev and published by Nova Publishers. This book was released on 2005 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemometrics is the chemical discipline that uses mathematical, statistical and other methods employing formal logic: to design or select optimal measurement procedures and experiments, and -- to provide maximum relevant chemical information by analysing chemical data. Being conceived as a branch of analytical chemistry, chemometrics now is a general approach. It extracts relevant information out of measured data, regardless of their origin: chemical, physical, biological, etc. Chemometrics has been applied in different areas, and most successfully in multivariate calibration, pattern recognition, classification and discriminant analysis, multivariate modelling, and monitoring of processes. The main chemometric principle is a concept of hidden data structures that can be found using methods of multivariate data analysis. These are the well-known statistic tools such as partial least squares (PLS), soft independent modelling of class analogy (SIMCA), principal-component regression (PCR), wavelet analysis, and many others. Current activities of chemometricians fall into two main categories: (1) development of new methods for manipulating multivariate data and (2) new applications of the known chemometric techniques in different areas such as environment control, food industry, agriculture, medicine, and engineering.

Download or read book Quantum Chemistry Aided Design of Organic Polymers written by Jean-Marie Andr‚ and published by World Scientific. This book was released on 1991 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is intended for those who are interested in understanding the electronic structure and properties of polymers. The scope of the book is to provide the non-specialist reader with a comprehensive and unified description: (i) of quantum mechanical methods, mainly originating from quantum chemistry, to calculate the electronic properties of polymers, (ii) of their use for interpreting and predicting results in fields where the electronic structure is playing an important role, like the electrical conductivity and the non linear optical properties of conjugated polymers.It will also serve as a reference book to lecture graduate students on the electronic structure of polymers or more generally of quasi-one dimensional materials. In this framework, it is worth stressing that the quantum theory of polymers bridges the gap between chemistry and physics. Since no book of this kind involving a strong interaction between theoretical and experimental concepts is available at the moment, it will also meet a need for a timely monograph in a field of important and fast growing interest.

Download or read book Metal Oxide Nanoparticles 2 Volume Set written by Oliver Diwald and published by John Wiley & Sons. This book was released on 2021-09-14 with total page 903 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxide Nanoparticles A complete nanoparticle resource for chemists and industry professionals Metal oxide nanoparticles are integral to a wide range of natural and technological processes—from mineral transformation to electronics. Additionally, the fields of engineering, electronics, energy technology, and electronics all utilize metal oxide nanoparticle powders. Metal Oxide Nanoparticles: Formation, Functional Properties, and Interfaces presents readers with the most relevant synthesis and formulation approaches for using metal oxide nanoparticles as functional materials. It covers common processing routes and the assessment of physical and chemical particle properties through comprehensive and complementary characterization methods. This book will serve as an introduction to nanoparticle formulation, their interface chemistry and functional properties at the nanoscale. It will also act as an in-depth resource, sharing detailed information on advanced approaches to the physical, chemical, surface, and interface characterization of metal oxide nanoparticle powders and dispersions. Addresses the application of metal oxide nanoparticles and its economic impact Examines particle synthesis, including the principles of selected bottom-up strategies Explores nanoparticle formulation—a selection of processing and application routes Discusses the significance of particle surfaces and interfaces on structure formation, stability and functional materials properties Covers metal oxide nanoparticle characterization at different length scales With this valuable resource, academic researchers, industrial chemists, and PhD students can all gain insight into the synthesis, properties, and applications of metal oxide nanoparticles.

Download or read book Molecular Design written by A.L. Horvath and published by Elsevier. This book was released on 2012-12-02 with total page 1505 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a systematic presentation of the methods that have been developed for the interpretation of molecular modeling to the design of new chemicals. The main feature of the compilation is the co-ordination of the various scientific disciplines required for the generation of new compounds. The five chapters deal with such areas as structure and properties of organic compounds, relationships between structure and properties, and models for structure generation. The subject is covered in sufficient depth to provide readers with the necessary background to understand the modeling techniques. The book will be of value to chemists in industries involved in the manufacture of organic chemicals such as solvents refrigerants, blood substitutes, etc. It also serves as a reference work for researchers, academics, consultants, and students interested in molecular design.