Chemical Reactivity in Quantum Mechanics and Information Theory
Chemical Reactivity in Quantum Mechanics and Information Theory

Author: Roman F Nalewajski

Publisher: Elsevier

Published: 2022-11-17

Total Pages: 354

ISBN-13: 0323956238

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Chemical Reactivity in Quantum Mechanics and Information Theory introduces a thermodynamic-like description of molecular systems and provides an objective treatment of their fragments. The book formulates adequate entropic tools for probing in chemical terms and the electronic structure of molecules and rationalizing reactivity principles. It covers the information origins of chemical bonds, covalent/ionic composition, trends in molecular stability and reactivity, equilibrium polarizations and charge-transfer reconstructions of reactive complexes, as well as the phase/current promotions of molecular substrates. In addition, the book introduces a precise descriptor of molecular fragments and clarifies mostly intuitive semantics of several chemical concepts. Readers will find a precise and unbiased description of chemical reactivity phenomena in Donor-Acceptor systems in terms of quantum states and generalized concepts of Information/Communication theories. - Generates a new basis for understanding the rules governing molecular processes, information origins of chemical bonding, and its covalent/ionic composition - Provides an objective approach to classical issues in modern reactivity theory - Offers a unifying information-theoretic perspective on electronic states

Graph Theoretical Approaches to Chemical Reactivity
Graph Theoretical Approaches to Chemical Reactivity

Author: Danail D. Bonchev

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 291

ISBN-13: 9401112029

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The progress in computer technology during the last 10-15 years has enabled the performance of ever more precise quantum mechanical calculations related to structure and interactions of chemical compounds. However, the qualitative models relating electronic structure to molecular geometry have not progressed at the same pace. There is a continuing need in chemistry for simple concepts and qualitatively clear pictures that are also quantitatively comparable to ab initio quantum chemical calculations. Topological methods and, more specifically, graph theory as a fixed-point topology, provide in principle a chance to fill this gap. With its more than 100 years of applications to chemistry, graph theory has proven to be of vital importance as the most natural language of chemistry. The explosive development of chemical graph theory during the last 20 years has increasingly overlapped with quantum chemistry. Besides contributing to the solution of various problems in theoretical chemistry, this development indicates that topology is an underlying principle that explains the success of quantum mechanics and goes beyond it, thus promising to bear more fruit in the future.

The Application of Quantum Mechanics in Reactivity of Molecules
The Application of Quantum Mechanics in Reactivity of Molecules

Author: Sérgio F. Sousa

Publisher: MDPI

Published: 2021-03-19

Total Pages: 182

ISBN-13: 3036506586

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Over recent decades, the increase in computational resources, coupled with the popularity of competitive quantum mechanics alternatives (particularly DFT), has promoted the widespread penetration of quantum mechanics calculations into a variety of fields targeting the reactivity of molecules. This book presents a selection of original research papers and review articles illustrating diverse applications of quantum mechanics in the study of problems involving molecules and their reactivity.

Chemical Reactivity
Chemical Reactivity

Author: Savaş Kaya

Publisher: Elsevier

Published: 2023-05-15

Total Pages: 502

ISBN-13: 0323906281

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The growth of technology for chemical assessment has led to great developments in the investigation of chemical reactivity in recent years, but key information is often dispersed across many different research fields. Exploring both traditional and advanced methods, Chemical Reactivity, Volume 2: Approaches and Applications present the latest approaches and strategies for the computational assessment of chemical reactivity.Following an insightful introduction, the book begins with an overview of conformer searching techniques before progressing to explore numerous different techniques and methods, including confined environments, quantum similarity descriptors, volume-based thermodynamics and polarizability. A unified approach to the rules of aromaticity is followed by methods for assessing interaction energies and the role of electron density for varied different analyses. Algorithms for confirmer searching, partitioning and a whole range of quantum chemical methods are also discussed.Consolidating the knowledge of a global team of experts in the field, Chemical Reactivity, Volume 2: Approaches and Applications is a useful resource for both students and researchers interested in applying and refining their use of the latest approaches for assessing chemical reactivity in their own work. - Compiles a broad range of contemporary methods and approaches for reactivity and structure prediction - Highlights the application of chemical reactivity strategies for the investigation of such areas as aromaticity, halogen bonds, and electronic materials - Includes discussion of computational tools for exploring molecular spaces from different angles, including interaction energies, quantum similarity, and electron density

Electron Density
Electron Density

Author: Pratim Kumar Chattaraj

Publisher: John Wiley & Sons

Published: 2024-09-30

Total Pages: 613

ISBN-13: 1394217625

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Discover theoretical, methodological, and applied perspectives on electron density studies and density functional theory Electron density or the single particle density is a 3D function even for a many-electron system. Electron density contains all information regarding the ground state and also about some excited states of an atom or a molecule. All the properties can be written as functionals of electron density, and the energy attains its minimum value for the true density. It has been used as the basis for a quantum chemical computational method called Density Functional Theory, or DFT, which can be used to determine various properties of molecules. DFT brings out a drastic reduction in computational cost due to its reduced dimensionality. Thus, DFT is considered to be the workhorse for modern computational chemistry, physics as well as materials science. Electron Density: Concepts, Computation and DFT Applications offers an introduction to the foundations and applications of electron density studies and analysis. Beginning with an overview of major methodological and conceptual issues in electron density, it analyzes DFT and its major successful applications. The result is a state-of-the-art reference for a vital tool in a range of experimental sciences. Readers will also find: A balance of fundamentals and applications to facilitate use by both theoretical and computational scientists Detailed discussion of topics including the Levy-Perdew-Sahni equation, the Kohn Sham Inversion problem, and more Analysis of DFT applications including the determination of structural, magnetic, and electronic properties Electron Density: Concepts, Computation and DFT Applications is ideal for academic researchers in quantum, theoretical, and computational chemistry and physics.

Polish Quantum Chemistry from Kołos to Now
Polish Quantum Chemistry from Kołos to Now

Author: Monika Musial

Publisher: Elsevier

Published: 2023-06-05

Total Pages: 438

ISBN-13: 0443185956

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Polish Quantum Chemistry from Kolos to Now, Volume 87 provides a survey of contributions coauthored by Polish scientists working in Poland, and in European and American Universities. Sections in this release include Review: From the Kolos-Wolniewicz calculations to the quantum-electrodynamic treatment of the hydrogen molecule: competition between theory and experiment, Review: How to make symmetry-adapted perturbation theory more accurate, Review: Advanced models of coupled cluster theory for the ground, excited and ionized states, Can orbital basis sets compete with explicitly correlated ones for few-electron systems?, Converging high-level equation-of-motion coupled-cluster energetics with the help of Monte Carlo and selected configuration interaction, and more. Additional chapters cover Coupled cluster downfolding techniques: a review of existing applications in classical and quantum computing for chemical systems, Exploring the attosecond laser-driven electron dynamics in the hydrogen molecule with different real-time time-dependent configuration interaction approaches, Molecular systems in spatial confinement: variation of linear and nonlinear electrical response of molecules in the bond dissociation processes, and much more. - Updates on the latest developments and performance of SAPT - Presents key theory and applications of high precision calculations for few electron systems - Includes discussions on the development and applications of the DFT approach

Principles and Applications of Quantum Chemistry
Principles and Applications of Quantum Chemistry

Author: V.P. Gupta

Publisher: Academic Press

Published: 2015-10-15

Total Pages: 480

ISBN-13: 0128035013

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Principles and Applications of Quantum Chemistry offers clear and simple coverage based on the author's extensive teaching at advanced universities around the globe. Where needed, derivations are detailed in an easy-to-follow manner so that you will understand the physical and mathematical aspects of quantum chemistry and molecular electronic structure. Building on this foundation, this book then explores applications, using illustrative examples to demonstrate the use of quantum chemical tools in research problems. Each chapter also uses innovative problems and bibliographic references to guide you, and throughout the book chapters cover important advances in the field including: Density functional theory (DFT) and time-dependent DFT (TD-DFT), characterization of chemical reactions, prediction of molecular geometry, molecular electrostatic potential, and quantum theory of atoms in molecules. - Simplified mathematical content and derivations for reader understanding - Useful overview of advances in the field such as Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) - Accessible level for students and researchers interested in the use of quantum chemistry tools

Perspectives in Electronic Structure Theory
Perspectives in Electronic Structure Theory

Author: Roman F. Nalewajski

Publisher: Springer Science & Business Media

Published: 2012-03-26

Total Pages: 727

ISBN-13: 3642201792

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The understanding in science implies insights from several different points of view. Alternative modern outlooks on electronic structure of atoms and molecules, all rooted in quantum mechanics, are presented in a single text. Together these complementary perspectives provide a deeper understanding of the localization of electrons and bonds, the origins of chemical interaction and reactivity behavior, the interaction between the geometric and electronic structure of molecules, etc. In the opening two parts the basic principles and techniques of the contemporary computational and conceptual quantum chemistry are presented, within both the wave-function and electron-density theories. This background material is followed by a discussion of chemical concepts, including stages of the bond-formation processes, chemical valence and bond-multiplicity indices, the hardness/softness descriptors of molecules and reactants, and general chemical reactivity/stability principles. The insights from Information Theory, the basic elements of which are briefly introduced, including the entropic origins and Orbital Communication Theory of the chemical bond, are the subject of Part IV. The importance of the non-additive (interference) information tools in exploring patterns of chemical bonds and their covalent and ionic components will be emphasized.

The Application of Quantum Mechanics in Reactivity of Molecules
The Application of Quantum Mechanics in Reactivity of Molecules

Author: Sérgio F. Sousa

Publisher:

Published: 2021

Total Pages: 182

ISBN-13: 9783036506593

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Over recent decades, the increase in computational resources, coupled with the popularity of competitive quantum mechanics alternatives (particularly DFT), has promoted the widespread penetration of quantum mechanics calculations into a variety of fields targeting the reactivity of molecules. This book presents a selection of original research papers and review articles illustrating diverse applications of quantum mechanics in the study of problems involving molecules and their reactivity.

Collision Theory and Statistical Theory of Chemical Reactions
Collision Theory and Statistical Theory of Chemical Reactions

Author: S. G. Christov

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 336

ISBN-13: 3642931421

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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.