Exploring Chemistry With Electronic Structure Methods

This corrected second edition contains new material which includes solvent effects, the treatment of singlet diradicals, and the fundamentals of computaional chemistry. "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 Hueckel 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.

This volume focuses on the use of quantum theory to understand and explain experiments in organic chemistry. High level ab initio calculations, when properly performed, are useful in making quantitative distinctions between various possible interpretations of structures, reactions and spectra. Chemical reasoning based on simpler quantum models is, however, essential to enumerating the likely possibilities. The simpler models also often suggest the type of wave function likely to be involved in ground and excited states at various points along reaction paths. This preliminary understanding is needed in order to select the appropriate higher level approach since most higher level models are designed to describe improvements to some reasonable zeroth order wave function. Consequently, most of the chapters in this volume begin with experimental facts and model functions and then progress to higher level theory only when quantitative results are required.In the first chapter, Zimmerman discusses a wide variety of thermal and photochemical reactions of organic molecules. Gronert discusses the use of ab initio calculations and experimental facts in deciphering the mechanism of ?-elimination reactions in the gas phase. Bettinger et al focus on carbene structures and reactions with comparison of the triplet and singlet states. Next, Hrovat and Borden discuss more general molecules with competitive triplet and singlet contenders for the ground state structure. Cave explains the difficulties and considerations involved with many of the methods and illustrates the difficulties by comparing with the UV spectra of short polyenes. Jordan et al discuss long-range electron transfer using model compounds and model Hamiltonians. Finally, Hiberty discusses the breathing orbital valence bond model as a different approach to introducing the crucial åã correlation that is known to be important in organic reactions.

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.

0Keywords:“This treatise is a pedogogically oriented collection of 22 chapters chosen to comprehensively present the quantum mechanics of electronic phenomena in molecules. It is an excellent effort to match increases in the physical understanding of chemistry with the astonishing advances in digital computer power and accessibility … The two-volume set is a necessary addition to chemistry libraries or research group holdings.”J. Am. Chem. Soc.

On the occasion of the fourth International Conference on Industrial and Applied Mathematics!, we decided to organize a sequence of 4 minisymposia devoted to the mathematical aspects and the numerical aspects of Quantum Chemistry. Our goal was to bring together scientists from different communities, namely mathematicians, experts at numerical analysis and computer science, chemists, just to see whether this heterogeneous set of lecturers can produce a rather homogeneous presentation of the domain to an uninitiated audience. To the best of our knowledgde, nothing of this kind had never been tempted so far. It seemed to us that it was the good time for doing it, both . because the interest of applied mathematicians into the world of computational chemistry has exponentially increased in the past few years, and because the community of chemists feels more and more concerned with the numerical issues. Indeed, in the early years of Quantum Chemistry, the pioneers (Coulson, Mac Weeny, just to quote two of them) used to solve fundamental equations modelling toy systems which could be simply numerically handled in view of their very limited size. The true difficulty arose with the need to model larger systems while possibly taking into account their interaction with their environment. Hand calculations were no longer possible, and computing science came into the picture.