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Books > Science & Mathematics > Chemistry > Physical chemistry > Quantum & theoretical chemistry
In recent years the fundamental concepts and applied methodologies of molecular similarity analysis have experienced a revolutionary development. Motivated by the increased degree of understanding of elementary molecular properties on the levels ranging from fundamental quantum chemistry to the complex interactions of biomolecules, and aided by the spectacular progress in computer technology and access to computer power, the area has opened up to many new ideas and new approaches. This book covers topics in quantum similarity approaches, electron density shape analysis methods, and it provides better theoretical understanding of molecular similarity. Additionally, quantitative shape analysis, especially activity relations (QShAR) and the prediction of the pharmacological or toxicological effects of molecules in the related context of quantum QSAR (QQSAR). This volume written by the experts in the various subfields of molecular similarity, provides a collection of the most recent ideas, advances, and methodologies. It is the hope of the Editors that by representing these topics within a single volume, the readers will find a balanced overview of the status of the field. We also hope that the book will serve as a tool for selecting and assessing the best approach for various new types of problems of molecular similarity that may arise and it will provide a set of easy references for further studies and applications.
This book focuses on chemical reactions and processing under extreme conditions-how materials react with highly concentrated active species and/or in a very confined high-temperature and high-pressure volume. Those ultimate reaction environments created by a focused laser beam, discharges, ion bombardments, or microwaves provide characteristic nano- and submicron-sized products and functional nanostructures. The book explores the chemistry and processing of metals and non-metals as well as molecules that are strongly dependent on the energy deposition processes and character of the materials. Descriptions of a wide range of topics are given from the perspective of a variety of research methodologies, material preparations, and applications. The reader is led to consider and review how a high-energy source interacts with materials, and what the key factors are that determine the quality and quantity of nanoproducts and nano-processing.
This book embraces all physiochemical aspects of the structure and molecular dynamics of water, focusing on its role in biological objects, e.g. living cells and tissue, and in the formation of functionally active structures of biological molecules and their ensembles. Water is the single most abundant chemical found in all living things. It offers a detailed look into the latest modern physical methods for studying the molecular structure and dynamics of the water and provides a critical analysis of the existing literature data on the properties of water in biological objects. Water as a chemical reagent and as a medium for the formation of conditions for enzymatic catalysis is a core focus of this book. Although well suited for active researchers, the book as a whole, as well as each chapter on its own, can be used as fundamental reference material for graduate and undergraduate students throughout chemistry, physics, biophysics and biomedicine.
This textbook presents a concise comparison of catalytic and biocatalytic systems outlining their catalytic properties and peculiarities. Moreover, it presents a brief introduction to the science of catalysis and attempts to unify different catalytic systems into a single, conceptually coherent structure. In fact, molecular dynamics and complexity may occur in both catalysts and biocatalysts, with many similarities in both their structural configuration and operational mechanisms. Moreover, the interactions between the different components of the catalytic system that are important in defining the overall activity, including the nature of active sites are discussed. Each chapter includes end of chapter questions supported by an online instructor solution manual. This textbook will be useful for undergraduate and graduate chemistry and biochemistry students.
The 12th JerusaLem'Symposium was devoted to the exciting sub- ject of CataLysis in Chemistry and Biochemistry. As usuaL in these Sym- posia Theory and Experiment have been considered simuLtaneousLy in dis- cussions> invoLving renowned experts from many countries. We wish to thank aLL those who made this meeting possibLe and contributed to its success: the Baron de RothschiLd whose continuous generosity is at the source of these gatherings, the IsraeL Academy of Sciences and Humanities which offers us the cordiaL hospitaLity of its impressive and beautifuL buiLding and gardens and the Hebrew University of JerusaLem, faithfuL cosponsor of the Symposia. THE MACROMOLECULAR ELECTROSTATIC EFFECT IN BIOCHEMICAL ~EACTIVITY OF THE NUCLEIC ACIDS. BERNARD PULUIAN Institut de BioLogie Physico-Chimique, Laboratoire de Biochimie Theorique, aSSOCle au C. N. R. S. , 13, rue P. et M. Curie, Paris 75005, France. 1. INTRODUCTION The roLe of the macromoLecuLe and of its overaLL structure upon the reactivity of its reaction site(s) represents one of the fundamentaL probLems in the theory of cataLysis. The most impressive and most fre- quentLy considered exampLes occur in the fieLd of proteins where the probLem generaLLy consists of accounting for the enhancement of the reaction rate at the active site or at the coenzyme with respect to modeL systems, devoid of the macromoLecuLar superstructure. Different effects have been considered as possibLy responsibLe for the infLuence of the macromoLecuLe on such LocaLized-site reactions. I do not have the time to summarize or discuss them here.
This book is intended as an introductory text. It starts at the very fundamentals of the interaction of light and matter and progresses through the laws of light absorption, instrumentation and standards to the newer chemometric techniques. Other chapters cover colour, structural aspects of UV spectroscopy, detection in high performace liquid chromatography and flourescence.
Modern approaches to the theoretical computation and experimental determination of NMR shielding tensors are described in 29 papers based on lectures presented at the NATO ARW. All of the most popular computational methods are reviewed and recent progress is described in their application to chemical, biochemical, geochemical and materials science problems. Experimental studies on NMR shieldings in gases, liquids and solids are also included, with special emphasis placed upon the relationship between NMR shielding and geometric structure and upon tests of the accuracy of the various computational methods. Qualitative MO schemes and semi-empirical approaches are also considered in the light of the computational results. This should be a valuable book for anyone interested in how the NMR shielding tensor can be used to determine the geometric and electronic structures of molecules and solids.
This book describes a unique combination of quantum chemical methods for calculating the basic physical properties of luminescent materials, or phosphors. These solid inorganic materials containing an optically active dopant are key players in several major fields of societal interest, including energy-efficient lighting, solar cells, and medical imaging. The novel ab initio methods described in this book are especially designed to target the crowded and complex electronic excited states of lanthanide activators in inorganic solids. The book is well suited to both new and experienced researchers alike and appeals to a broad range of theoretical and experimental backgrounds. The material presented enables an adept understanding of elaborate calculations, which, in tandem with experiments, give essential insight into difficult luminescence problems and quandaries, thus fully preparing the reader for an educated search for new functional luminescent materials
Conjugated polymers suoh as polyaoetylene (CH)x polyphenylene (C6H4)x' poly thiophene (C4H2S)x' etc. , which are insulators in their pristine state, can be brought to the metallic state after "doping" with ohemioal speoies whioh oan be either eleotron donors or I aoceptors. . This doping prooess involves a oharge transfer between the dopant moleoule and the polymer ohain whioh are then supposed to be spatially olose to each other. It follows that the meohanism of doping must be oonsidered as an aotual interoalation process, which will greatly affeot the struotural oharacteristios of the starting material, as well as its morphology, as has been observed during the 2 intercalation of graphite and layered compounds . In parallel with these modifioations, the band struoture of the system changes yielding a new set of eleotronio properties. It is evident therefore that the struotural and eleotronio properties are intimately related, and must be studied simultaneously in the same system to give reliable information. A great number of studies have been devoted to the structural and electronic properties of conjugated polymers after a chemical or 2 electrochemical doping process . Most of these concern the properties of the system for a given dopant concentration. With this approach a universal pioture of the polymer/dopant system is very diffioult to obtain, as a comparison between different experiments is very hazardous. On the other hand, only a small number of measurements have been performed during the continuous electroohemioal doping of various polymers.
This book describes fundamental theory and recent advances of sum frequency generation (SFG) spectroscopy. SFG spectroscopy is widely used as a powerful tool of surface characterization, although theoretical interpretation of the obtained spectra has been a major bottleneck for most users. Recent advances in SFG theory have brought about a breakthrough in the analysis methods beyond conventional empirical ones, and molecular dynamics (MD) simulation of SFG spectroscopy allows for simultaneous understanding of observed spectra and interface structure in unprecedented detail. This book explains these recently understood theoretical aspects of SFG spectroscopy by the major developer of the theory. The theoretical topics are treated at basic levels for undergraduate students and are described in relation to computational chemistry, such as molecular modeling and MD simulation, toward close collaboration of SFG spectroscopy and computational chemistry in the near future.
This book presents the latest theoretical studies giving new predictions and interpretations on the quantum correlation in molecular dynamics induced by ultrashort laser pulses. The author quantifies the amount of correlation in terms of entanglement by employing methods developed in quantum information science, in particular applied to the photoionization of a hydrogen molecule. It is also revealed that the photoelectron-ion correlation affects the vibrational dynamics of the molecular ion and induces the attosecond-level time delay in the molecular vibration. Furthermore, the book also presents how molecular vibration can couple to photons in a plasmoic nanocavity. Physicists and chemists interested in the ultrafast molecular dynamics would be the most relevant readers. They can learn how we can employ the quantum-information-science tools to understand the correlation in the molecular dynamics and why we should consider the correlation between the photoelectron and the molecular ion to describe the ion's dynamics. They can also learn how to treat a molecule coupled to photons in a nanocavity. All the topics are related to the state-of-the-art experiments, and so, it is important to publish these results to enhance the understanding and to induce new experiments to confirm the theory presented.
This book is intended for theoretical and experimental researchers who are interested in ferroelectrics and advanced memory. After introducing readers to dielectric, perovskites, advanced memories, and ferroelectric, it explains quantum simulation. Then, using molecular orbital calculation results, it explains the ferroelectric mechanism in perovskite titanium oxides in concrete terms. Lastly, the book examines the materials designed for high-performance ferroelectrics and discusses the future of high-speed memory.
At the American Chemical Society meeting in Philadelphia, Pennsylvania, U.S.A., a symposium was organized entitled, "Comparison of Ab Initio Quantum Chemistry with Experiment: State-of-the-Art." The intent of the symposium was to bring together forefront experimen talists, who perform the types of clean, penetrating experiments that are amenable to thorough theoretical analysis, with inventive theore ticians who have developed high accuracy ab initio methods that are capable of competing favorably with experiment, to assess the current applicability of theoretical methods in chemistry. Contributions from many of those speakers (see Appendix A) plus others selected for their expertise in the subject are contained in this volume. Such a book is especially timely, since with the recent develop ment of new, more accurate and powerful ab initio methods coupled with the exceptional progress achieved in computational equipment, ab initio quantum chemistry is now often able to offer a third voice to resolve experimental discrepancies, assist essentially in the interpre tation of experiments, and frequently, provide quantitatively accurate results for molecular properties that are not available from experiment."
This book explores the philosophy and the foundations of quantum chemistry. It features chapters written by experts in the field. The contributions analyze quantum chemistry as a discipline, in particular, its relation with both chemistry and physics from the viewpoint of realism and reduction. Coverage includes such topics as quantum chemistry as an "in-between" discipline, molecular structure and quantum mechanics, quantum chemical models, and atoms and molecules in quantum chemistry. The interest of this book is twofold. First, the contributions aim to update and refresh the discussions regarding the foundations of quantum chemistry. Second, they seek to develop new philosophical perspectives that this discipline can suggest to philosophers of science. From its origins, quantum chemistry filled a problematic position in the disciplinary space. On the one hand, it is a branch of theoretical chemistry. On the other hand, it appeals essentially to theoretical tools coming from physics. This peculiar position triggered conceptual questions about its own identity. Inside this book, readers will find updated discussions on the foundations and the philosophy of this complex discipline.
The importance of molecular recognition in chemistry and biology is reflected in a recent upsurge in relevant research, promoted in particular by high-profile initiatives in this area in Europe, the USA and Japan. Although molecular recognition is necessarily microscopic in origin, its consequences are de facto macroscopic. Accordingly, a text that starts with intermolecular interactions between simple molecules and builds to a discussion of molecular recognition involving larger scale systems is timely. This book was planned with such a development in mind. The book begins with an elementary but rigorous account of the various types of forces between molecules. Chapter 2 is concerned with the hydrogen bond between pairs of simple molecules in the gas phase, with particular reference to the preferred relative orientation of the pair and the ease with which this can be distorted. This microscopic view continues in chapter 3 wherein the nature of interactions between solute molecules and solvents or between two or more solutes is examined from the experimental standpoint, with various types of spectroscopy providing the probe of the nature of the interactions. Molecular recognition is central to the catalysis of chemical reactions, especially when bonds are to be broken and formed under the severe con straint that a specific configuration is to result, as in the production of enan tiotopically pure compounds. This important topic is considered in chapter 4.
This volume provides the reader with the most up-to-date and relevant knowledge on the reactivity of metals located in zeolite materials, either in framework or extra-framework positions, and the way it is connected with the nature of the chemical environment provided by the host. Since the first report of the isomorphous substitution of titanium in the framework of zeolites giving rise to materials with unusual catalytic properties, the incorporation of many other metals have been investigated with the aim for developing catalysts with improved performance in different reactions. The continuous expansion of the field, both in the variety of metals and zeolite structures, has been accompanied by an increasing focus on the relationship between the reactivity of metal centers and their unique chemical environment. The concepts covered in this volume are of interest to people working in the field of inorganic and physical chemistry, catalysis and chemical engineering, but also for those more interested in theoretical approaches to chemical reactivity. In particular the volume is useful to postgraduate students conducting research in the design, synthesis and catalytic performance of metal-containing zeolites in both academic and application contexts.
The focus of this thesis is the computational modelling of transition metal bimetallic (nanoalloy) clusters. More specifically, the study of Pd-Pt, Ag-Pt, Au-Au and Pd-Au as a few tens of atoms in the gas phase. The author used a combination of global optimization techniques - coupled with a Gupta-type empirical many-body potential - and Density Functional Theory (DFT) calculations to study the structures, bonding and chemical ordering, as well as investigate the chemisorptions of hydrogen and carbon monoxide on bimetallic clusters. This research is highly relevant to experimental catalytic studies and has resulted in more than seven publications in international journals.
This book offers a clearly written and highly accessible account of two different aspects of carbohydrate chemistry. Carbohydrates are an essential component of life and have many important biological functions, but the details of how carbohydrates interact with other biomolecules to mediate biological signalling remain unclear. Firstly, this thesis details innovative methods to mine protein structural data to uncover new features of carbohydrate-based interactions. It also explains these findings using physical chemistry, specifically CH-pi interactions associated with the properties of the interacting partners. Carbohydrates are also critical for tissue growth and development, yet are underexploited in the materials science that underpins much of regenerative medicine. As such, the second part of this thesis describes a diverse array of techniques ranging from synthetic chemistry and enzymatic synthesis to prepare a wide variety of carbohydrates, and materials chemistry to prepare glycosylated hydrogels, to cell biology to determine the effects on cellular development for tissue engineering applications.
There have been several recent breakthroughs in the supramolecular domain: larger molecular components are being synthesized; 2D layers involving multiple recognition sites; crystals with intricate building blocks are being designed; more components are being used in assembly and self-assembly "algorithms" (some having molecular weights as high as 15,000); and there is an increasing versatility in applications. The difficulty in characterizing and obtaining structural information on such large assemblies has increased to such a level that no single technique is now adequate. Various methods have now been upgraded and are being combined: X-ray diffraction (structures with hundreds of independent atoms), NMR, AFM/STM (manipulation of a single molecule), FAB/MS, time-resolved techniques up to the picosecond range, new computational approaches, and others. The present book aims to shed light on the most recent developments in both the synthesis of novel assemblies and on current methods for their characterization.
MICHAEL T. POPE AND ACHIM MULLER Department of Chemistry, Georgetown University, Washington, DC 20057-2222, U.S.A.; Department of Chemistry, University of Bielefeld, D-4BOO Bielefeld 1, F.R.G. Polyoxometalates, from their discovery and early development in the final decades of the 19th century to their current significance in disciplines as diverse as chemistry, mathematics, and medicine, continue to display surprisingly novel structures, unexpected reactivities and applications, and to attract increasing attention worldwide. Most of the contributors to the present volume participated in the workshop held at the Center for Interdisciplinary Research at the University of Bielefeld, July 15-17, 1992. The choice of topics illustrates some of the variety of directions and fields in which polyoxometalates can play an important role. Although many of the leading polyoxometalate research groups are represented here, we regret that time constraints, financial limitations, and in some cases difficulties of communication did not allow us to include significant and imp- tant work from other groups outside Europe and North America. In the following we briefly review the current status of the field of po- oxometalates.
Absolute concepts of time and energy are integral to standard thermal physics, but background independent systems are devoid of them. This thesis explores the foundational question of generalising equilibrium statistical mechanics to background independent systems, and applies the resulting formulation to non-perturbative discrete quantum gravity. It offers a discussion of the rich interface of thermal physics and quantum gravity in this context, providing a broad contextualisation of such topics. This work details how standard tools from many-body physics can be generalised to discrete quantum gravity labelled with graph-based, or dual polyhedral, quanta that are common to various approaches like tensorial group field theory, loop quantum gravity, dynamical triangulations and lattice quantum gravity. It provides a systematic investigation, both conceptual and technical, of quantum gravitational Gibbs states, thermofield double vacuum states, and their application in condensate cosmology to probe questions of Big Bang singularity resolution and geometric inflation.
The Fourth International Congress in Quantum Chemistry under the auspices of the International Academy of Molecular Quantum Science in Menton, France was arranged at Uppsala University, Uppsala, Sweden, during the period June 14 - 19, 1982, in close collaboration with the University of Florida. The previous congresses were held in Menton 1973, New Orleans 1976, and Kyoto 1979, and the 1985 congress is tentatively planned to be held in the province of Quebec, Canada. The Congress consisted of six symposia in various areas of quantum chemistry, solid-state theory, and quantum bi ology. The meeting was attended by about 450 scientists from 45 different nations, and a total of more than 300 scientific papers were presented. Even the poster contri butions were given some plenary time. These proceedings contain the text of the plenary lec tures as well as the chairmen's introductions, whereas the contributed papers will be published in the International Journal of Quantum Chemistry, (John Wiley & Sons, New York) in the regular January - April 1983 issues."
This book focuses on the modern development of techniques for analysis of the hierarchical structure of polymers from both the experimental and theoretical points of view. Starting with molecular and crystal symmetry, the author explains fundamental and professional methods, such as wide- and small-angle X-ray scattering, neutron diffraction, electron diffraction, FTIR and Raman spectroscopy, NMR, and synchrotron radiation. In addition, the author explains another indispensable method, computer simulation, which includes energy calculation, lattice dynamics, molecular dynamics, and quantum chemistry. These various methods are described in a systematic way so that the reader can utilize them for the purpose of 3D structure analysis of polymers. Not only such analytical knowledge but also the preparation techniques of samples necessary for these measurements and the methods of analyzing the experimental data collected in this way are given in a concrete manner. Examples are offered to help master the principles of how to clarify the static structures and dynamic structural changes in the phase transitions of various kinds of crystalline polymers that are revealed by these novel methods. The examples are quite useful for readers who want to apply these techniques in finding practical solutions to concrete problems that are encountered in their own research. The principal audience for this book is made up of young professional researchers including those working in industry, but it can also be used as an excellent reference for graduate-level students. This book is the first volume of a two-volume set with Structural Science of Crystalline Polymers: A Microscopically Viewed Structure-Property Relationship being the second volume by the same author.
From the beginnings of modern chemistry, molecular structure has been a lively area of research and speculation. For more than half a century spectroscopy and other methods have been available to characterize the structures and shapes of molecules, particularly those that are rigid. However, most molecules are at least to some degree non-rigid and this non-rigidity plays an important role in such diverse areas as biological activity, energy transfer, and chemical reactivity. In addition, the large-amplitude vibrations present in non-rigid molecules give rise to unusual low-energy vibrational level patterns which have a dramatic effect on the thermodynamic properties of these systems. Only in recent years has a coherent picture of the energetics and dynamics of the conformational changes inherent in non-rigid (and semi-rigid) molecules begun to emerge. Advances have been made in a number of different experimental areas: vibrational (infrared and Raman) spectroscopy, rotational (microwave) spectroscopy, electron diffraction, and, most recently, laser techniques probing both the ground and excited electronic states. Theoretically, the proliferation of powerful computers coupled with scientific insight has allowed both empirical and ab initio methods to increase our understanding of the forces responsible for the structures and energies of non-rigid systems. The development of theory (group theoretical methods and potential energy surfaces) to understand the unique characteristics of the spectra of these floppy molecules has also been necessary to reach our present level of understanding. The thirty chapters in this volume contributed by the key speakers at the Workshop are divided over the various areas. Both vibrational and rotational spectroscopy have been effective at determining the potential energy surfaces for non-rigid molecules, often in a complementary manner. Recent laser fluorescence work has extended these types of studies to electronic excited states. Electronic diffraction methods provide radial distribution functions from which both molecular structures and compositions of conformational mixtures can be found. Ab initio calculations have progressed substantially over the past few years, and, when carried out at a sufficiently high level, can accurately reproduce (or predict ahead of time) experimental findings. Much of the controversy of the ARW related to the question of when an ab initio is reliable. Since the computer programs are readily available, many poor calculations have been carried out. However, excellent results can be obtained from computations when properly done. A similar situation exists for experimental analyses. The complexities of non-rigid molecules are many, but major strides have been taken to understand their structures and conformational processes.
The 14th Jerusalem Symposium continued the tradition of the pleasant and exciting meetings which once a year gather distinguished scientists, the world's most renowned experts in specific fields of quantum chemistry and biochemistry, in the impressive surroundings of the Israel Academy of Sciences and Humanities. The subject discussed this year - Intermolecular forces - is one of the utmost interest for all molecular sciences. I wish to thank all those who made this meeting possible and contributed toits success: the Baron Edmond de Rothschild whose continuous generosity guarantees the perenniality of our venture, t e Israel Academy of Sciences and in particular its Vice-President, Pr fes sor Yoshua Jortner for his devoted contribution to the organization and holding of this meeting, the high authorities of the Hebrew Uni versity of Jerusalem and in particular the Rector Meshulamfor their constant support and Dr. Pierre Claverie for his efficient help in the preparation of the program. Mrs Abigail Hyam and Mrs MyriamYogev must be thanked for their contribution to the efficiency and success of the local arrangements. Bernard Pullman ix B.Pullman ed.}, IntermolecularForces, ix. Copyright (c)1981byD.ReidelPublishingCompany. INTERMOLECULAR FORCES: WHAT CAN BE LEARNED FROM AB INITIO CALCULATIONS? Advan der Avoird Institute of Theoretical Chemistry, University of Nijmegen, Toernooiveld, Nijmegen, The Netherlands. 1. INTRODUCTION Various experiments, suc as elastic or rotationally inelastic molecular beamscattering(1,2 and spectroscopic studies of so-cafled Van der Waals molecules(3,4), have been designed especially to provide information about the Van der Waals interactions between molecules." |
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