Quantum Chemistry Approaches to Chemisorption and Heterogeneous Catalysis
Quantum Chemistry Approaches to Chemisorption and Heterogeneous Catalysis

Author: F. Ruette

Publisher: Springer Science & Business Media

Published: 2013-03-14

Total Pages: 379

ISBN-13: 9401728259

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The development of "high-tech" materials in contemporary industries is deeply related to a detailed understanding of specific surface properties of catalysts which make particular reactions possible. But this understanding presupposes that there exists a body of theory capable of explaining situations not easily accessible to experimental methods and of relating experimental findings among themselves and with theoretical constructs. For these reasons, theoretical developments in surface physics and surface chemistry of transition metal compounds have been of paramount importance in promoting progress in catalysis, electronic devices, corrosion, etc. Although a great variety of spectroscopic methods for analyzing solids and surfaces at molecular scale have been introduced in recent years, nevertheless, many questions about the adsorption sites and intermediates, the effect of promoters, the poisoning of active sites, the nature of segregation of impurities, the process of surface reconstruction, the mechanisms of reactions, etc. have remained unanswered simply because of the great complexity of surface phenomena. It is in this sense that quantum mechanical method- combined with experimental data - may shed some light on the microscopic properties of new surface materials.

Theoretical and Computational Approaches to Interface Phenomena
Theoretical and Computational Approaches to Interface Phenomena

Author: J.T. Golab

Publisher: Springer Science & Business Media

Published: 2013-11-11

Total Pages: 249

ISBN-13: 148991319X

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Many chemical processes that are important to society take place at boundaries between phases. Understanding these processes is critical in order for them to be subject to human control. The building of theoretical or computational models of them puts them into a theoretical framework in terms of which the behavior of the system can be understood on a detailed level. Theoretical and computational models are often capable of giving descriptions of interfacial phenomena that are more detailed, on a molecular level, than can be obtained through experimental observation. Advances in computer hardware have also made possible the treatment of larger and chemically more interesting systems. The study of interfacial phenomena is a multi-disciplinary endeavor which requires collaboration and communication among researchers in different fields and across different types of institutions. Because there are many important problems in this field much effort is being expended to understand these processes by industrial laboratories as well as by groups at universities. Our conference titled "Theoretical and Computational Approaches to Interface Phenomena" held at South Dakota State University, August 2-4, 1993 brought together over thirty scientists from industry and academia and three countries in the western hemisphere to discuss the modeling of interfacial phenomena.

Computational Approaches to Biochemical Reactivity
Computational Approaches to Biochemical Reactivity

Author: Gábor Náray-Szabó

Publisher: Springer Science & Business Media

Published: 2002-03-31

Total Pages: 396

ISBN-13: 9781402004155

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A quantitative description of the action of enzymes and other biological systems is both a challenge and a fundamental requirement for further progress in our und- standing of biochemical processes. This can help in practical design of new drugs and in the development of artificial enzymes as well as in fundamental understanding of the factors that control the activity of biological systems. Structural and biochemical st- ies have yielded major insights about the action of biological molecules and the mechanism of enzymatic reactions. However it is not entirely clear how to use this - portant information in a consistent and quantitative analysis of the factors that are - sponsible for rate acceleration in enzyme active sites. The problem is associated with the fact that reaction rates are determined by energetics (i. e. activation energies) and the available experimental methods by themselves cannot provide a correlation - tween structure and energy. Even mutations of specific active site residues, which are extremely useful, cannot tell us about the totality of the interaction between the active site and the substrate. In fact, short of inventing experiments that allow one to measure the forces in enzyme active sites it is hard to see how can one use a direct experimental approach to unambiguously correlate the structure and function of enzymes. In fact, in view of the complexity of biological systems it seems that only computers can handle the task of providing a quantitative structure-function correlation.

Computational Chemistry And Chemical Engineering - Proceedings Of The Third Unam-cray Supercomputing Confrence
Computational Chemistry And Chemical Engineering - Proceedings Of The Third Unam-cray Supercomputing Confrence

Author: Gerardo Cisneros

Publisher: World Scientific

Published: 1997-10-31

Total Pages: 421

ISBN-13: 9814545805

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This book provides a wide-ranging and up-to-date description of state-of-the-art computational methodologies in chemistry and chemical engineering. It displays a representative mix of topics on the computation and modeling of chemical systems of all sizes, from the very small (atomic) to the very large (industrial). The book constitutes an excellent overview for graduate students as well as a critical update for researchers.

Dynamics of Surfaces and Reaction Kinetics in Heterogeneous Catalysis
Dynamics of Surfaces and Reaction Kinetics in Heterogeneous Catalysis

Author: G.F. Froment

Publisher: Elsevier

Published: 1997-09-03

Total Pages: 611

ISBN-13: 0080530621

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Many processes of the chemical industry are based upon heterogeneous catalysis. Two important items of these processes are the development of the catalyst itself and the design and optimization of the reactor. Both aspects would benefit from rigorous and accurate kinetic modeling, based upon information on the working catalyst gained from classical steady state experimentation, but also from studies using surface science techniques, from quantum chemical calculations providing more insight into possible reaction pathways and from transient experimentation dealing with reactions and reactors. This information is seldom combined into a kinetic model and into a quantitative description of the process. Generally the catalytic aspects are dealt with by chemists and by physicists, while the chemical engineers are called upon for mechanical aspects of the reactor design and its control. The symposium "Dynamics of Surfaces and Reaction Kinetics in Heterogeneous Catalysis" aims at illustrating a more global and concerted approach through a number of prestigious keynote lectures and severely screened oral and poster presentations.

Electron, Spin and Momentum Densities and Chemical Reactivity
Electron, Spin and Momentum Densities and Chemical Reactivity

Author: Paul G. Mezey

Publisher: Springer Science & Business Media

Published: 2006-04-11

Total Pages: 328

ISBN-13: 030646943X

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The electron density of a non-degenerate ground state system determines essentially all physical properties of the system. This statement of the Hohenberg–Kohn theorem of Density Functional Theory plays an exceptionally important role among all the fundamental relations of Molecular Physics. In particular, the electron density distribution and the dynamic properties of this density determine both the local and global reactivities of molecules. High resolution experimental electron densities are increasingly becoming available for more and more molecules, including macromolecules such as proteins. Furthermore, many of the early difficulties with the determination of electron densities in the vicinity of light nuclei have been overcome. These electron densities provide detailed information that gives important insight into the fundamentals of molecular structure and a better understanding of chemical reactions. The results of electron density analysis are used in a variety of applied fields, such as pharmaceutical drug discovery and biotechnology. If the functional form of a molecular electron density is known, then various molecular properties affecting reactivity can be determined by quantum chemical computational techniques or alternative approximate methods.

Elementary Reaction Steps in Heterogeneous Catalysis
Elementary Reaction Steps in Heterogeneous Catalysis

Author: R.W. Joyner

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 482

ISBN-13: 9401116938

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This book comprises the proceedings of a NATO sponsored Advanced Research Workshop held from 1st November to 6th November 1992 in the delightful Chateau de Florans, Bedoin, Vaucluse, France and entitled 'Elementary Reaction Steps in Heterogeneous Catalysis. ' The organisers are grateful to the Science Committee of NATO for their support of this meeting. This is believed to be the first wide ranging NATO ARW in the field of heterogeneous catalysis for 20 years, following a previous venture organised in Sardinia by Basolo and Burwell, of Northwestern University, Illinois, USA [1]. This volume collects the lecture presentations and reports on the lively Panel discussions. The idea for the meeting evolved from a series of International Symposia on Quantum Chemistry and Mechanism in Heterogeneous Catalysis. The first of these was held in Lyon, France in 1986, the second in Krakow, Poland in 1988 and the third in Berkeley, California in 1990. The organising committee of the present meeting was Bernard Bigot, France, Tony Farragher, Netherlands, Richard Joyner, UK, Mme. Danielle Olivier, France, and Rutger van Santen, Netherlands, (Chairman). We wish to thank all members of the committee but in particular Bernard Bigot, who undertook the very extensive work involved in the local organisation with consummate skill and made our stay in Provence a great pleasure. Bernard Bigot's secretary, Mme. Marie-Noelle Coscat and Richard Joyner's secretary, Mrs. Pat Gibbs, also deserve our considerable thanks. There were fifty-four participants from eleven countries.

Quantum Mechanical Electronic Structure Calculations with Chemical Accuracy
Quantum Mechanical Electronic Structure Calculations with Chemical Accuracy

Author: S. Langhoff

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 451

ISBN-13: 9401101930

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The principal focus of this volume is to illustrate the level of accuracy currently achievable by ab initio quantum chemical calculations. While new developments in theory are discussed to some extent, the major emphasis is on a comparison of calculated properties with experiment. This focus is similar to the one taken in a book, Comparison of Ab Initio Quantum Chemistry with Experiment for Small Molecules, edited by Rodney Bartlett (Reidel, 1984). However, the phenomenal improvement in both theoretical methods and computer architecture have made it possible to obtain accurate results for rather large molecular systems. This is perhaps best illustrated in this volume by the chapter entitled `Spectroscopy of Large Organic Molecules' by Bjorn Roos and coworkers. For example, the electronic spectra of the nucleic acid base monomer structures shown on the front cover have been obtained using a fully correlated ab initio study. For researchers, teachers and students in chemistry and physics.

The Role of Rydberg States in Spectroscopy and Photochemistry
The Role of Rydberg States in Spectroscopy and Photochemistry

Author: C. Sándorfy

Publisher: Springer Science & Business Media

Published: 2006-04-11

Total Pages: 524

ISBN-13: 0306469383

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The aim of this volume is to offer a balanced overview of molecular Rydberg spectroscopy as it has developed over recent decades. Recent evolution has split Rydberg spectroscopy into two apparently distinct fields: the one concerns the low (n=3-5) Rydberg states, the other the very high (typically EMn/EM”150) Rydberg states. The former is aimed at spectral levels where Rydberg, valence-shell, and intermediate-type states interact, with a variety of photochemical consequences. The latter considers states extremely close to the ionization limit, from whereionization is possible with a very slight amount of additional energy. Recently developed techniques make it possible to produce ions in well-defined electronic, vibrational and rotational states, including states resulting from spin-orbit or Jahn-Teller splitting. It is then possible to study the structure and reactions of such state-selected ions as well as those of the corresponding neutral molecules. These techniques amount to badly needed high resolution photoelectron spectroscopy.