| computational chemistry basis sets: Basis Sets in Computational Chemistry Eva Perlt, 2021-05-06 This book addresses the construction and application of the major types of basis sets for computational chemistry calculations. In addition to a general introduction, it includes mathematical basics and a discussion of errors arising from incomplete or inappropriate basis sets. The different chapters introduce local orbitals and orbital localization as well as Slater-type orbitals and review basis sets for special applications, such as those for correlated methods, solid-state calculations, heavy atoms and time-dependent adaptable Gaussian bases for quantum dynamics simulations. This detailed review of the purpose of basis sets, their design, applications, possible problems and available solutions provides graduate students and beginning researchers with information not easily obtained from the available textbooks and offers valuable supporting material for any quantum chemistry or computational chemistry course at the graduate and/or undergraduate level. This book is also useful as a guide for researchers who are new to computational chemistry but are willing to extend their research tools by applying such methods. |
| computational chemistry basis sets: Computational Quantum Chemistry Charles M. Quinn, 2002-02-28 Computational Quantum Chemistry removes much of the mystery of modern computer programs for molecular orbital calculations by showing how to develop Excel spreadsheets to perform model calculations and investigate the properties of basis sets. Using the book together with the CD-ROM provides a unique interactive learning tool. In addition, because of the integration of theory with working examples on the CD-ROM, the reader can apply advanced features available in the spreadsheet to other applications in chemistry, physics, and a variety of disciplines that require the solution of differential equations.This book and CD-ROM makes a valuable companion for instructors, course designers, and students. It is suitable for direct applications in practical courses in theoretical chemistry and atomic physics, as well as for teaching advanced features of Excel in IT courses. |
| computational chemistry basis sets: Basis Sets in Computational Chemistry Eva Perlt, 2021 This book addresses the construction and application of the major types of basis sets for computational chemistry calculations. In addition to a general introduction, it includes mathematical basics and a discussion of errors arising from incomplete or inappropriate basis sets. The different chapters introduce local orbitals and orbital localization as well as Slater-type orbitals and review basis sets for special applications, such as those for correlated methods, solid-state calculations, heavy atoms and time-dependent adaptable Gaussian bases for quantum dynamics simulations. This detailed review of the purpose of basis sets, their design, applications, possible problems and available solutions provides graduate students and beginning researchers with information not easily obtained from the available textbooks and offers valuable supporting material for any quantum chemistry or computational chemistry course at the graduate and/or undergraduate level. This book is also useful as a guide for researchers who are new to computational chemistry but are willing to extend their research tools by applying such methods. . |
| computational chemistry basis sets: Computational Quantum Chemistry Masoud Soroush, 2018-10-16 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 |
| computational chemistry basis sets: Computational Chemistry and Molecular Modeling K. I. Ramachandran, Gopakumar Deepa, Krishnan Namboori, 2008-05-20 The gap between introductory level textbooks and highly specialized monographs is filled by this modern textbook. It provides in one comprehensive volume the in-depth theoretical background for molecular modeling and detailed descriptions of the applications in chemistry and related fields like drug design, molecular sciences, biomedical, polymer and materials engineering. Special chapters on basic mathematics and the use of respective software tools are included. Numerous numerical examples, exercises and explanatory illustrations as well as a web site with application tools (http://www.amrita.edu/cen/ccmm) support the students and lecturers. |
| computational chemistry basis sets: Molecular Modeling Basics Jan H. Jensen, 2010-04-26 Molecular modeling is becoming an increasingly important part of chemical research and education as computers become faster and programs become easier to use. The results, however, have not become easier to understand. Addressing the need for a workshop-oriented book, Molecular Modeling Basics provides the fundamental theory needed to understand |
| computational chemistry basis sets: Symmetry-Adapted Basis Sets John Avery, 2012 In theoretical physics, theoretical chemistry and engineering, one often wishes to solve partial differential equations subject to a set of boundary conditions. This gives rise to eigenvalue problems of which some solutions may be very difficult to find. For example, the problem of finding eigenfunctions and eigenvalues for the Hamiltonian of a many-particle system is usually so difficult that it requires approximate methods, the most common of which is expansion of the eigenfunctions in terms of basis functions that obey the boundary conditions of the problem. The computational effort needed in such problems can be much reduced by making use of symmetry-adapted basis functions. The conventional method for generating symmetry-adapted basis sets is through the application of group theory, but this can be difficult. This book describes an easier method for generating symmetry-adapted basis sets automatically with computer techniques. The method has a wide range of applicability, and can be used to solve difficult eigenvalue problems in a number of fields. The book is of special interest to quantum theorists, computer scientists, computational chemists and applied mathematicians. |
| computational chemistry basis sets: Modern Quantum Chemistry Attila Szabo, Neil S. Ostlund, 2012-06-08 This graduate-level text explains the modern in-depth approaches to the calculation of electronic structure and the properties of molecules. Largely self-contained, it features more than 150 exercises. 1989 edition. |
| computational chemistry basis sets: Methods of Electronic Structure Theory Henry F. Schaefer, 2013-06-29 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. |
| computational chemistry basis sets: Computational Methods in Lanthanide and Actinide Chemistry Michael Dolg, 2015-02-17 The f-elements and their compounds often possess an unusually complex electronic structure, governed by the high number of electronic states arising from open f-shells as well as large relativistic and electron correlation effects. A correct theoretical description of these elements poses the highest challenges to theory. Computational Methods in Lanthanide and Actinide Chemistry summarizes state-of-the-art electronic structure methods applicable for quantum chemical calculations of lanthanide and actinide systems and presents a broad overview of their most recent applications to atoms, molecules and solids. The book contains sixteen chapters, written by leading experts in method development as well as in theoretical investigations of f-element systems. Topics covered include: Relativistic configuration interaction calculations for lanthanide and actinide anions Study of actinides by relativistic coupled cluster methods Relativistic all-electron approaches to the study of f- element chemistry Relativistic pseudopotentials and their applications Gaussian basis sets for lanthanide and actinide elements Applied computational actinide chemistry This book will serve as a comprehensive reference work for quantum chemists and computational chemists, both those already working in, and those planning to enter the field of quantum chemistry for f-elements. Experimentalists will also find important information concerning the capabilities of modern quantum chemical methods to assist in the interpretation or even to predict the outcome of their experiments. |
| computational chemistry basis sets: Mathematical Challenges from Theoretical/Computational Chemistry National Research Council, Division on Engineering and Physical Sciences, Commission on Physical Sciences, Mathematics, and Applications, Committee on Mathematical Challenges from Computational Chemistry, 1995-03-29 Computational methods are rapidly becoming major tools of theoretical, pharmaceutical, materials, and biological chemists. Accordingly, the mathematical models and numerical analysis that underlie these methods have an increasingly important and direct role to play in the progress of many areas of chemistry. This book explores the research interface between computational chemistry and the mathematical sciences. In language that is aimed at non-specialists, it documents some prominent examples of past successful cross-fertilizations between the fields and explores the mathematical research opportunities in a broad cross-section of chemical research frontiers. It also discusses cultural differences between the two fields and makes recommendations for overcoming those differences and generally promoting this interdisciplinary work. |
| computational chemistry basis sets: Modern Electronic Structure Theory D. R. Yarkony, 1995 Modern Electronic Structure Theory provides a didactically oriented description of the latest computational techniques in electronic structure theory and their impact in several areas of chemistry. The book is aimed at first year graduate students or college seniors considering graduate study in computational chemistry, or researchers who wish to acquire a wider knowledge of this field. |
| computational chemistry basis sets: Introduction to Computational Chemistry Frank Jensen, 2016-12-14 Introduction to Computational Chemistry 3rd Edition provides a comprehensive account of the fundamental principles underlying different computational methods. Fully revised and updated throughout to reflect important method developments and improvements since publication of the previous edition, this timely update includes the following significant revisions and new topics: Polarizable force fields Tight-binding DFT More extensive DFT functionals, excited states and time dependent molecular properties Accelerated Molecular Dynamics methods Tensor decomposition methods Cluster analysis Reduced scaling and reduced prefactor methods Additional information is available at: www.wiley.com/go/jensen/computationalchemistry3 |
| computational chemistry basis sets: Essentials of Computational Chemistry Christopher J. Cramer, 2013-04-29 Essentials of Computational Chemistry provides a balanced introduction to this dynamic subject. Suitable for both experimentalists and theorists, a wide range of samples and applications are included drawn from all key areas. The book carefully leads the reader thorough the necessary equations providing information explanations and reasoning where necessary and firmly placing each equation in context. |
| computational chemistry basis sets: Computational Chemistry David Young, 2004-04-07 A practical, easily accessible guide for bench-top chemists, thisbook focuses on accurately applying computational chemistrytechniques to everyday chemistry problems. Provides nonmathematical explanations of advanced topics incomputational chemistry. Focuses on when and how to apply different computationaltechniques. Addresses computational chemistry connections to biochemicalsystems and polymers. Provides a prioritized list of methods for attacking difficultcomputational chemistry problems, and compares advantages anddisadvantages of various approximation techniques. Describes how the choice of methods of software affectsrequirements for computer memory and processing time. |
| computational chemistry basis sets: Annual Reports in Computational Chemistry , 2015-11-29 Annual Reports in Computational Chemistry provides timely and critical reviews of important topics in computational chemistry as applied to all chemical disciplines. Topics covered include quantum chemistry, molecular mechanics, force fields, chemical education, and applications in academic and industrial settings. Focusing on the most recent literature and advances in the field, each article covers a specific topic of importance to computational chemists. - Quantum chemistry - Molecular mechanics - Force fields - Chemical education and applications in academic and industrial settings |
| computational chemistry basis sets: Theory and Applications of Computational Chemistry Clifford Dykstra, Gernot Frenking, Kwang Kim, Gustavo Scuseria, 2011-10-13 Computational chemistry is a means of applying theoretical ideas using computers and a set of techniques for investigating chemical problems within which common questions vary from molecular geometry to the physical properties of substances. Theory and Applications of Computational Chemistry: The First Forty Years is a collection of articles on the emergence of computational chemistry. It shows the enormous breadth of theoretical and computational chemistry today and establishes how theory and computation have become increasingly linked as methodologies and technologies have advanced. Written by the pioneers in the field, the book presents historical perspectives and insights into the subject, and addresses new and current methods, as well as problems and applications in theoretical and computational chemistry. Easy to read and packed with personal insights, technical and classical information, this book provides the perfect introduction for graduate students beginning research in this area. It also provides very readable and useful reviews for theoretical chemists.* Written by well-known leading experts * Combines history, personal accounts, and theory to explain much of the field of theoretical and compuational chemistry* Is the perfect introduction to the field |
| computational chemistry basis sets: Ideas of Quantum Chemistry Lucjan Piela, 2006-11-28 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 |
| computational chemistry basis sets: Computational Quantum Chemistry Joseph J W McDouall, 2015-11-09 Computational Quantum Chemistry presents computational electronic structure theory as practised in terms of ab initio waveform methods and density functional approaches. Getting a full grasp of the field can often prove difficult, since essential topics fall outside of the scope of conventional chemistry education. This professional reference book provides a comprehensive introduction to the field. Postgraduate students and experienced researchers alike will appreciate Joseph McDouall's engaging writing style. The book is divided into five chapters, each providing a major aspect of the field. Electronic structure methods, the computation of molecular properties, methods for analysing the output from computations and the importance of relativistic effects on molecular properties are also discussed. Links to the websites of widely used software packages are provided so that the reader can gain first hand experience of using the techniques described in the book. |
| computational chemistry basis sets: Molecular Electronic-Structure Theory Trygve Helgaker, Poul Jorgensen, Jeppe Olsen, 2014-08-11 Ab initio quantum chemistry has emerged as an important tool in chemical research and is appliced to a wide variety of problems in chemistry and molecular physics. Recent developments of computational methods have enabled previously intractable chemical problems to be solved using rigorous quantum-mechanical methods. This is the first comprehensive, up-to-date and technical work to cover all the important aspects of modern molecular electronic-structure theory. Topics covered in the book include: * Second quantization with spin adaptation * Gaussian basis sets and molecular-integral evaluation * Hartree-Fock theory * Configuration-interaction and multi-configurational self-consistent theory * Coupled-cluster theory for ground and excited states * Perturbation theory for single- and multi-configurational states * Linear-scaling techniques and the fast multipole method * Explicity correlated wave functions * Basis-set convergence and extrapolation * Calibration and benchmarking of computational methods, with applications to moelcular equilibrium structure, atomization energies and reaction enthalpies. Molecular Electronic-Structure Theory makes extensive use of numerical examples, designed to illustrate the strengths and weaknesses of each method treated. In addition, statements about the usefulness and deficiencies of the various methods are supported by actual examples, not just model calculations. Problems and exercises are provided at the end of each chapter, complete with hints and solutions. This book is a must for researchers in the field of quantum chemistry as well as for nonspecialists who wish to acquire a thorough understanding of ab initio molecular electronic-structure theory and its applications to problems in chemistry and physics. It is also highly recommended for the teaching of graduates and advanced undergraduates. |
| computational chemistry basis sets: Computational Organic Chemistry Steven M. Bachrach, 2014-04-07 The Second Edition demonstrates how computational chemistry continues to shed new light on organic chemistry The Second Edition of author Steven Bachrach’s highly acclaimed Computational Organic Chemistry reflects the tremendous advances in computational methods since the publication of the First Edition, explaining how these advances have shaped our current understanding of organic chemistry. Readers familiar with the First Edition will discover new and revised material in all chapters, including new case studies and examples. There’s also a new chapter dedicated to computational enzymology that demonstrates how principles of quantum mechanics applied to organic reactions can be extended to biological systems. Computational Organic Chemistry covers a broad range of problems and challenges in organic chemistry where computational chemistry has played a significant role in developing new theories or where it has provided additional evidence to support experimentally derived insights. Readers do not have to be experts in quantum mechanics. The first chapter of the book introduces all of the major theoretical concepts and definitions of quantum mechanics followed by a chapter dedicated to computed spectral properties and structure identification. Next, the book covers: Fundamentals of organic chemistry Pericyclic reactions Diradicals and carbenes Organic reactions of anions Solution-phase organic chemistry Organic reaction dynamics The final chapter offers new computational approaches to understand enzymes. The book features interviews with preeminent computational chemists, underscoring the role of collaboration in developing new science. Three of these interviews are new to this edition. Readers interested in exploring individual topics in greater depth should turn to the book’s ancillary website www.comporgchem.com, which offers updates and supporting information. Plus, every cited article that is available in electronic form is listed with a link to the article. |
| computational chemistry basis sets: Computational Chemistry Errol G. Lewars, 2007-05-08 Computational chemistry has become extremely important in the last decade, being widely used in academic and industrial research. Yet there have been few books designed to teach the subject to nonspecialists. Computational Chemistry: Introduction to the Theory and Applications of Molecular and Quantum Mechanics is an invaluable tool for teaching and researchers alike. The book provides an overview of the field, explains the basic underlying theory at a meaningful level that is not beyond beginners, and it gives numerous comparisons of different methods with one another and with experiment. The following concepts are illustrated and their possibilities and limitations are given: - potential energy surfaces; - simple and extended Hückel methods; - ab initio, AM1 and related semiempirical methods; - density functional theory (DFT). Topics are placed in a historical context, adding interest to them and removing much of their apparently arbitrary aspect. The large number of references, to all significant topics mentioned, should make this book useful not only to undergraduates but also to graduate students and academic and industrial researchers. |
| computational chemistry basis sets: Multiconfigurational Quantum Chemistry Björn O. Roos, Roland Lindh, Per ke Malmqvist, Valera Veryazov, Per-Olof Widmark, 2016-08-08 The first book to aid in the understanding of multiconfigurational quantum chemistry, Multiconfigurational Quantum Chemistry demystifies a subject that has historically been considered difficult to learn. Accessible to any reader with a background in quantum mechanics and quantum chemistry, the book contains illustrative examples showing how these methods can be used in various areas of chemistry, such as chemical reactions in ground and excited states, transition metal and other heavy element systems. The authors detail the drawbacks and limitations of DFT and coupled-cluster based methods and offer alternative, wavefunction-based methods more suitable for smaller molecules. |
| computational chemistry basis sets: Computational Chemistry and Molecular Modeling K. I. Ramachandran, Gopakumar Deepa, Krishnan Namboori, 2008-06-13 The gap between introductory level textbooks and highly specialized monographs is filled by this modern textbook. It provides in one comprehensive volume the in-depth theoretical background for molecular modeling and detailed descriptions of the applications in chemistry and related fields like drug design, molecular sciences, biomedical, polymer and materials engineering. Special chapters on basic mathematics and the use of respective software tools are included. Numerous numerical examples, exercises and explanatory illustrations as well as a web site with application tools (http://www.amrita.edu/cen/ccmm) support the students and lecturers. |
| computational chemistry basis sets: Introduction to Relativistic Quantum Chemistry Kenneth G. Dyall, Knut Faegri Jr., 2007-04-19 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. |
| computational chemistry basis sets: Exploring Chemistry with Electronic Structure Methods James B. Foresman, AEleen Frisch, 1996 |
| computational chemistry basis sets: Handbook of Gaussian Basis Sets Raymond Poirier, 1985 |
| computational chemistry basis sets: Gaussian Basis Sets for Molecular Calculations S. Huzinaga, J. Andzelm, E. Radzio-Andzelm, Y. Sakai, H. Tatewaki, M. Klobukowski, 2012-12-02 Physical Sciences Data, Volume 16: Gaussian Basis Sets for Molecular Calculations provides information pertinent to the Gaussian basis sets, with emphasis on lithium, radon, and important ions. This book discusses the polarization functions prepared for lithium through radon for further improvement of the basis sets. Organized into three chapters, this volume begins with an overview of the basis set for the most stable negative and positive ions. This text then explores the total atomic energies given by the basis sets. Other chapters consider the distinction between diffuse functions and polarization function. This book presents as well the exponents of polarization function. The final chapter deals with the Gaussian basis sets. This book is a valuable resource for chemists, scientists, and research workers. |
| computational chemistry basis sets: An Introduction to Electronic Structure Theory Nadia T. Paulsen, 2020-09-24 In An Introduction to Electronic Structure Theory, Quantum Information Theory is applied to donor-acceptor systems. Reaction stages and charge-transfer phenomena are described, continuities of probability and phase distributions are explored, and resultant information descriptors combining classical and nonclassical contributions are summarized.The authors describe the most efficient method for studying the electronic structure of solids, the magnetic dilution method, or the study of the magnetic susceptibility of diluted solid solutions of paramagnetic oxides in diamagnetic isomorphous matrices.A review of the mathematical modeling and investigation of the electronic structure of some nanomaterials, composite materials, and graphene is presented using the Parameterized Model number 3 (PM3) semi-empirical method.A basic introduction of electronic structure theory with commonly used notation is provided, as well as its applications for studying the physical properties of materials.Lastly, based on a concept of different prescription for different correlation, a multireference Brillouin-Wigner perturbation scheme with improved virtual orbitals is presented as an accurate and affordable computational protocol for treating electronic states plagued by quasidegeneracy. |
| computational chemistry basis sets: Computational Thermochemistry Karl K. Irikura, 1998 Comprises 20 contributions which grew from the August 1996 symposium. Representative paper topics include estimating phase- change enthalpies and entropies, electrostatic-covalent model parameters for molecular modeling, complete basis-set thermochemistry and kinetics, modeling free energies of solvation and transfer, use of density functional methods to compute heats of reaction, and a density functional study of periodic trends in bond energies. Together the contributions describe all the major methods used for estimating or predicting molecular thermochemistry. Appends information on software and databases for thermochemistry, essential statistical thermodynamics, and worked examples. Annotation copyrighted by Book News, Inc., Portland, OR |
| computational chemistry basis sets: Ramping it Up Laura Kelly McKemmish, 2015 For decades, all-Gaussian basis sets have dominated molecular quantum chemistry, despite some of their less desirable properties. In particular, gaussian basis functions cannot describe the nuclear-electron cusp and consequently large numbers of high exponents gaussians are present in core basis functions to try to describe the inner core electron distribution adequately. This is despite the fact that core electron distribution changes little in response to changing molecular environments and is not an important contribution to chemical energetics that chemists are generally interested in (reaction energies, ionisation energies, isomerisation energies and so on). The principal reason for the dominance of gaussian basis sets is that accurate evaluation of two-electron integral evaluation in these basis sets is far quicker than for other competing types of basis sets. This thesis seeks to change this. We reintroduce a ramp basis function, which has a non-zero nuclearelectron cusp and can therefore describe the inner core accurately and efficiently. This ramp function has compact support, which greatly reduces the difficulty of two-electron integral evaluation, but means it cannot describe valence electron distributions. Thus, gaussian basis functions are added to describe valence electrons to form a mixed ramp-gaussian basis set. To simplify the development of this new class of basis set, we modify only the core basis function in 6-31G (6-31+G) to produce R-31G (R-31+G). These novel rampified basis sets have very similar chemistry to their parent basis sets in atoms and molecules in Hartree-Fock (HF), density functional theory (DFT) and Moller-Plesset 2 Theory (MP2) calculations. The mixed ramp-gaussian basis sets are vastly better than their parent basis sets at predicting electron density at the nucleus and in fact gives better performance than cc-pVQZ. Faster HF, DFT and MP2 calculations in large molecules would increase the speed of the most common types of computational chemistry calculations in the world. This thesis provides strong evidence that mixed ramp-Gaussian basis sets are a viable way to get these faster calculations without compromising chemical accuracy. A preliminary integral evaluation program, RampItUp, was developed in this thesis that calculates all one- and two-electron ramp-containing integrals for a mixed ramp-Gaussian basis set with S-ramps, sand p-gaussians. With the main caveat that two-electron screening is not performed in either basis set, the Fock build time for R-31+G is faster than in 6-31+G by about 10% for large linear molecules, e.g. fatty acids, with more than 20 heavy atoms. This demonstrates that fast integral evaluation is possible. This thesis provides strong justification for the inclusion of ramp-gaussian basis sets into mainstream quantum chemistry packages to allow the full benefits of these new type of basis sets to be experienced by the field as a whole. |
| computational chemistry basis sets: Beyond Born-Oppenheimer Michael Baer, 2006-03-31 INTRODUCING A POWERFUL APPROACH TO DEVELOPING RELIABLE QUANTUM MECHANICAL TREATMENTS OF A LARGE VARIETY OF PROCESSES IN MOLECULAR SYSTEMS. The Born-Oppenheimer approximation has been fundamental to calculation in molecular spectroscopy and molecular dynamics since the early days of quantum mechanics. This is despite well-established fact that it is often not valid due to conical intersections that give rise to strong nonadiabatic effects caused by singular nonadiabatic coupling terms (NACTs). In Beyond Born-Oppenheimer, Michael Baer, a leading authority on molecular scattering theory and electronic nonadiabatic processes, addresses this deficiency and introduces a rigorous approach--diabatization--for eliminating troublesome NACTs and deriving well-converged equations to treat the interactions within and between molecules. Concentrating on both the practical and theoretical aspects of electronic nonadiabatic transitions in molecules, Professor Baer uses a simple mathematical language to rigorously eliminate the singular NACTs and enable reliable calculations of spectroscopic and dynamical cross sections. He presents models of varying complexity to illustrate the validity of the theory and explores the significance of the study of NACTs and the relationship between molecular physics and other fields in physics, particularly electrodynamics. The first book of its king Beyond Born-Oppenheimer: * Presents a detailed mathematical framework to treat electronic NACTs and their conical intersections * Describes the Born-Oppenheimer treatment, including the concepts of adiabatic and diabatic frameworks * Introduces a field-theoretical approach to calculating NACTs, which offers an alternative to time-consuming ab initio procedures * Discusses various approximations for treating a large system of diabatic Schrödinger equations * Presents numerous exercises with solutions to further clarify the material being discussed Beyond Born-Oppenheimer is required reading for physicists, physical chemists, and all researchers involved in the quantum mechanical study of molecular systems. |
| computational chemistry basis sets: Numerical Methods for the Solution of Ill-Posed Problems A.N. Tikhonov, A. Goncharsky, V.V. Stepanov, Anatoly G. Yagola, 2013-03-09 Many problems in science, technology and engineering are posed in the form of operator equations of the first kind, with the operator and RHS approximately known. But such problems often turn out to be ill-posed, having no solution, or a non-unique solution, and/or an unstable solution. Non-existence and non-uniqueness can usually be overcome by settling for `generalised' solutions, leading to the need to develop regularising algorithms. The theory of ill-posed problems has advanced greatly since A. N. Tikhonov laid its foundations, the Russian original of this book (1990) rapidly becoming a classical monograph on the topic. The present edition has been completely updated to consider linear ill-posed problems with or without a priori constraints (non-negativity, monotonicity, convexity, etc.). Besides the theoretical material, the book also contains a FORTRAN program library. Audience: Postgraduate students of physics, mathematics, chemistry, economics, engineering. Engineers and scientists interested in data processing and the theory of ill-posed problems. |
| computational chemistry basis sets: Density Functional Theory David S. Sholl, Janice A. Steckel, 2011-09-20 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. |
| computational chemistry basis sets: Methods in Computational Chemistry Stephen Wilson, 2013-12-01 Recent years have seen the proliferation of new computer designs that employ parallel processing in one form or another in order to achieve maximum performance. Although the idea of improving the performance of computing machines by carrying out parts of the computation concurrently is not new (indeed, the concept was known to Babbage ), such machines have, until fairly recently, been confined to a few specialist research laboratories. Nowadays, parallel computers are commercially available and they are finding a wide range of applications in chemical calculations. The purpose of this volume is to review the impact that the advent of concurrent computation is already having, and is likely to have in the future, on chemical calculations. Although the potential of concurrent computation is still far from its full realization, it is already clear that it may turn out to be second in importance only to the introduction of the electronic digital computer itself. |
| computational chemistry basis sets: Thom H. Dunning, Jr. Angela K. Wilson, Kirk A. Peterson, David E. Woon, 2015-05-04 In this Festschrift celebrating the career of Thom H. Dunning, Jr., selected researchers in theoretical chemistry present research highlights on major developments in the field. Originally published in the journal Theoretical Chemistry Accounts, these outstanding contributions are now available in a hardcover print format, as well as a special electronic edition. This volume provides valuable content for all researchers in theoretical chemistry and will especially benefit those research groups and libraries with limited access to the journal. |
| computational chemistry basis sets: Introduction to Computational Chemistry Frank Jensen, 2016-11-28 Introduction to Computational Chemistry 3rd Edition provides a comprehensive account of the fundamental principles underlying different computational methods. Fully revised and updated throughout to reflect important method developments and improvements since publication of the previous edition, this timely update includes the following significant revisions and new topics: Polarizable force fields Tight-binding DFT More extensive DFT functionals, excited states and time dependent molecular properties Accelerated Molecular Dynamics methods Tensor decomposition methods Cluster analysis Reduced scaling and reduced prefactor methods Additional information is available at: www.wiley.com/go/jensen/computationalchemistry3 |
| computational chemistry basis sets: The Fundamentals of Density Functional Theory , 2012-12-06 Density functional methods form the basis of a diversified and very active area of present days computational atomic, molecular, solid state and even nuclear physics. A large number of computational physicists use these meth ods merely as a recipe, not reflecting too much upon their logical basis. One also observes, despite of their tremendeous success, a certain reservation in their acceptance on the part of the more theoretically oriented researchers in the above mentioned fields. On the other hand, in the seventies (Thomas Fermi theory) and in the eighties (Hohenberg-Kohn theory), density func tional concepts became subjects of mathematical physics. In 1994 a number of activities took place to celebrate the thirtieth an niversary of Hohenberg-Kohn-Sham theory. I took this an occassion to give lectures on density functional theory to senior students and postgraduates in the winter term of 1994, particularly focusing on the logical basis of the the ory. Preparing these lectures, the impression grew that, although there is a wealth of monographs and reviews in the literature devoted to density func tional theory, the focus is nearly always placed upon extending the practical applications of the theory and on the development of improved approxima tions. The logical foundadion of the theory is found somewhat scattered in the existing literature, and is not always satisfactorily presented. This situation led to the idea to prepare a printed version of the lecture notes, which resulted in the present text. |
| computational chemistry basis sets: Methods in Computational Chemistry Stephen Wilson, 2013-11-11 Thisvolume isdevotedtomethodsfor thestudyoftheeffectsofrelativity on theelectronicstructure ofatomsand molecules. The accurate descrip tionofrelativisticeffectsinheavyatomshaslongbeenrecognizedasoneof the central problems ofatomic physics. Contemporary relativistic atomic structure calculations can be performed almost routinely. Recent years have seen agrowinginterestin thestudyoftheeffects ofrelativityon the structureofmolecules. Even for molecularsystemscontainingatoms from thesecondrowoftheperiodictable theenergyassociatedwith relativistic effects is often larger than that arising from electron correlation. For moleculescontainingheavieratoms relativistic effects become increasingly important, andforsystemscontainingveryheavyatomsrelativityisknown todominatemanychemicalproperties. In this volum, one of the pioneers of relativistic atomic structure calculations, Ian P. Grant, providesadetailedsurveyofthecomputational techniquesemployedincontemporarystudiesoftheeffectsofrelativityon atomicstructure. Thisisanareaofresearchinwhichcalculationscanoften lead to a particularly impressive degreeofagreement between theoryand experiment. Furthermore, theseatomicstudies haveprovided manyofthe foundations of a fully relativistic quantum chemistry. However, the spherical symmetry ofatoms allows significantsimplificationsto bemade in their quantum mechanical treatment, simplifications which are not possibleinstudiesofmolecules. Inparticular, as is wellknown from non relativistictheoriesofmolecularelectronicstructure, itisalmostobligatory to invoke the algebraic approximation in molecular work and use finite basis set expansions. The problem of describing relativistic effects in molecules is addressed in Chapter2 by Stephen Wilson. This chapter is devotedtoab initiorelativisticmolecularstructurecalculationsinwhichall electrons are explicitly considered. The problem of induding relativistic effects in molecular studies is also addressed in Chapters3 and 4. In Chapter 3, Odd Gropen describes the use of relativistic effective core ix x Preface potentials in calculations on molecular systems involving heavy atoms. This approach can lead to more tractable algorithms than the methods described in Chapter2 and thus significantly extends the range of applications. The use of semiempirical methods has yielded a wealth of informationabouttheinfluenceofrelativityonthechemistryoftheheavier elements. Thisimportantarea is reviewed inChapter4 by Pekka Pyykk6. Finally, inChapter5, Harry M. |
| computational chemistry basis sets: Reviews in Computational Chemistry, Volume 1 Kenny B. Lipkowitz, Donald B. Boyd, 2009-09-22 This book is an account of current developments in computational chemistry, a new multidisciplinary area of research. Experts in computational chemistry, the editors use and develop techniques for computer-assisted molecular design. The core of the text itself deals with techniques for computer-assisted molecular design. The book is suitable for both beginners and experts. In addition, protocols and software for molecular recognition and the relationship between structure and biological activity of drug molecules are discussed in detail. Each chapter includes a mini-tutorial, as well as discussion of advanced topics. Special Feature: The appendix to this book contains an extensive list of available software for molecular modeling. |
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Discover everything about the word "COMPUTATIONAL" in English: meanings, translations, synonyms, pronunciations, examples, and grammar insights - all in one comprehensive guide.
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COMPUTATIONAL definition | Cambridge English Dictionary
COMPUTATIONAL meaning: 1. involving the calculation of answers, amounts, results, etc.: 2. using computers to study…. Learn more.
COMPUTATIONAL Definition & Meaning - Merriam-Webster
The meaning of COMPUTATION is the act or action of computing : calculation. How to use computation in a sentence.
Computation - Wikipedia
Mechanical or electronic devices (or, historically, people) that perform computations are known as computers. Computer science is an academic field that involves the study of computation.
Computational science - Wikipedia
Computational science, also known as scientific computing, technical computing or scientific computation (SC), is a division of science, and more specifically the Computer Sciences, …
Computational - Definition, Meaning & Synonyms - Vocabulary.com
Computational is an adjective referring to a system of calculating or "computing," or, more commonly today, work involving computers. Tasks with a lot of computational steps are best …
COMPUTATIONAL definition in American English - Collins Online …
Computational means using computers. Students may pursue research in any aspect of computational linguistics. Collins COBUILD Advanced Learner’s Dictionary. Copyright © …
Computational - definition of computational by ... - The Free …
Define computational. computational synonyms, computational pronunciation, computational translation, English dictionary definition of computational. n. 1. a. The act or process of …
COMPUTATIONAL - Definition & Translations | Collins English …
Discover everything about the word "COMPUTATIONAL" in English: meanings, translations, synonyms, pronunciations, examples, and grammar insights - all in one comprehensive guide.
What is computational thinking? - Introduction to computational
Learn about the four cornerstones of computational thinking including decomposition, pattern recognition, abstraction and algorithms.
Computational Definition & Meaning - YourDictionary
Computational definition: Of or relating to
computation.
