Our aim in this book is to present and enlarge upon those aspects of parallel computing that are needed by practitioners of computational science. Today al most all classical sciences, such as mathematics, physics, chemistry and biology, employ numerical methods to help gain insight into nature. In addition to the traditional numerical methods, such as matrix inversions and the like, a whole new field of computational techniques has come to assume central importance, namely the numerical simulation methods. These methods are much less fully developed than those which are usually taught in a standard numerical math ematics course. However, they form a whole new set of tools for research in the physical sciences and are applicable to a very wide range of problems. At the same time there have been not only enormous strides forward in the speed and capability of computers but also dramatic new developments in computer architecture, and particularly in parallel computers. These improvements offer exciting prospects for computer studies of physical systems, and it is the new techniques and methods connected with such computer simulations that we seek to present in this book, particularly in the light of the possibilities opened up by parallel computers. It is clearly not possible at this early stage to write a definitive book on simulation methods and parallel computing."

Considering aspects of symmetry rules in chemistry, one is faced with con tradictory terms as for example, "90 % concertedness" sometimes being used in literature. To accept conservation of orbital symmetry to be as controlled as inversion by alternative principles seems far more promising. The intention of this book is aimed at introducing a qualitative understanding of phase rela tions in electromagnetic interactions. Avoiding one-sided dogmatism we tried to demonstrate the importance of alternative principles as guidelines to the evolution of alternative order in chemical systems. Passing through the jungle of information it became extremly important to control again and again our insights into the ordering phenomena by experi ments under conditions as coherent as possible. We became more aware of the fact that chemistry - the science of "becoming" in complex systems - can not be understood by mechanistic details, i. e. THROUGHPUT-studies alone, because the mechanism is only true for the special system under inves tigation and does not offer a tool for the evolution of opposite order. We had to accept chemistry as a mediator between molecular physics and general epistemology. This quite unusual combination was directed by excel lent teachers and the realizations were made possible by enthusiastic, open minded coworkers (see references). The next target we will strive for on this journey will be to quantify the alternative principles, that means obtaining the order parameters of H. Haken (e. g. in asymmetric synthesis).

For more than 100 years the Beilstein Handbook has been publishing checked and evaluated data on organic compounds. It has become the major reference book for the chemical and physical properties of organic com pounds. The prediction of these physical properties was the subject of the Beilstein workshop. The ability to predict physical properties is for several reasons of great interest to the Beilstein Institute. It is of primary importance to be able to check the abstracted data for accuracy and to eliminate simple mistakes like typing errors. Presently all the work whether manuscript writing or evaluation of data is carried out manually. This is very time consuming, with the entry of Beilstein into electronic data gathering and publication, the opportunity for computerized consistency checking has become available. Contrary to belief, when one examines the Beilstein Handbook or Chemical Abstracts there is a dearth of chemical information. There are a great many compounds but few are well defined resulting in large gaps in the information available to the chemist. These information gaps could be filled by using algorithmic methods to estimate the properties of interest. An important question to answer is "What is the chemist's reaction to estimated data?" Will he accept it for use, within limits defined by the method, or will it be unacceptable and therefore detrimental for the data base. However if one could partly fill gaps in the data base the increase in the power of the search techniques would be marked."

In this text experts review experimental studies that directly reveal the relationship between the atomic structure and physical behavior of high-Tc superconductors. The thorough discussion centers on twins, twin boundaries, the vortex lattice, and magnetic and mechanical properties in connection with structural imperfections. Particular attention is paid to the role of the oxygen atom in the Y-Ba-Cu-O and La-Cu-O species. The experimental methods evaluated include electron and X-ray diffraction, electron microscopy, and M-ssbauer spectroscopy. This book makes extraordinarily valuable data obtained at the Institute of Solid State Physics at Chernogolovka accessible to the wider international community of researchers in superconductivity.

In recent years there has been growing interest in the nucleon-nucleon correl ations inside nuclei. In many respects the motions of the nucleons can be very well described by an overall mean field, so that the motion of each nucleon is governed by the mean field due to all the other nucleons. This concept underlies the Fermi-gas, Hartree-Fock and shell models and has enabled a range of nuclear properties to be calculated, often to surprising accuracy. It gradually became clear, however, that these mean-field models are limited by the effects due to the very strong interactions between the nucleons that occur at short distances; these are the short-range correlations. They are responsible for instance for the high-momentum components in the nucleon momentum dis tribution, and prevent the simultaneous description of the nuclear density and momentum distributions by the same mean field. It thus becomes necessary to develop methods for including the effects of nucleon correlations in nuclei, and these are the main subject of this book. Some related problems of nuclear structure were discussed in an earlier book by the same authors: Nucleon Momentum and Density Distributions in Nuclei (Clarendon Press, Oxford, 1988). The main aim of that book was to study the effects of nucleon-nucleon correlations, both short-range and tensor, on the nucleon momentum distribution, which is particularly sensitive to these correl ations, and on the nucleon density distribution."

Plasma Spectroscopy systematically develops the foundations of spectroscopy for plasmas subjected to quasi-monochromatic electric fields in the microwave or visible range. Such fields may be due to longitudinal Langmuir waves or low hybrid oscillations, which are excited in pulsed discharged or by high-current beams of charged particles. Even more important are the transverse fields present in the plasmas of tokamaks, laser fusion, and technological microwave discharges. This book is intended for researchers dealing with plasma spectroscopy, plasma diagnostics, high frequency and microwave discharges, laser induced discharges, particle and laser-beam interactions with plasmas, controlled fusion, and ionospheric and astrophysical plasmas. It describes methods for measuring the field and plasma parameters and discusses their practical application. It also presents new results on nonpertubative analysis of the interaction of quantum systems with a strong radiation field.

The quantum theory of magnetism is a well-developed part of contemporary solid-state physics. The basic concepts of this theory can be used to describe such important effects as ferromagnetic ordering oflocalized magnetic moments in crystals and ferromagnetism of metals produced by essentially delocalized electrons, as well as various types of mutual orientation of atomic magnetic moments in solids possessing different crystal lattices and compositions. In recent years, the spin-fluctuational approach has been developed, which can overcome some contradictions between "localized" and "itinerant" models in the quantum mechanics of magnetic crystals. These are only some of the principal achievements of quantum magnetic theory. Almost all of the known magnetic properties of solids can be qualitat ively explained on the basis of its concepts. Further developments should open up the possibility of reliable quantitative description of magnetic properties of solids. Unfortunately, such calculations based on model concepts appear to be very complicated and, quite often, not definite enough. The rather small number of parameters of qualitative models are usually not able to take into account the very different types of magnetic interactions that appear in crystals. Further development of magnetic theory requires quantitative information on electronic wave function in the crystal considered. This can be proved by electronic band structure and cluster calculations. In many cases the latter can be a starting point for quantitative calculations of parameters used in magnetic theory."

Solid-State NMR is a branch of Nuclear Magnetic Resonance which is presently experiencing a phase of strongly increasing popularity. The most striking evidence is the large number of contributions from Solid-State Resonance at NMR meetings, approaching that ofliquid state resonance. Important progress can be observed in the areas of methodological developments and applications to organic and inorganic matter. One volume devoted to more or less one of each of these areas has been published in the preceding three issues. This volume can be considered an addendum to this series. Selected methods and applications of Solid-State NMR are featured in three chapters. The first one treats the recoupling of dipolar interactions in solids, which are averaged by fast sample rotation. Following an introduction to effective Hamiltonians and Floquet theory, different types of experiment such as rotary resonance, dipolar chemical shift correlation spectroscopy, rotational resonance and multipulse recoupling are treated in the powerful Floquet formalism. In the second chapter, the different approaches to line narrowing of quadrupolar nuclei are reviewed in a. consistent formulation of double resonance (DaR) and dynamic angle spinning (DAS). Practical aspects of probe design are considered as well as advanced 2D experiments, sensitivity enhancement techniques, and spinning sideband manipulations. The use of such techniques dramatically increases the number of nuclei which can be probed in high resolution NMR spectroscopy. The final chapter describes new experimental approaches and results of structural studies of noncrystalline solids."

1. A.-R. Grimmer, Berlin, FRG; B. Bl}mich, Aachen, FRG: Introduction to Solid-State NMR 2. F. Laupretre, Paris, France: High-Resolution 13C NMRInvestigations of Local Dynamics in Bulk Polymers at Temperatures Below andAbove the Glass-Transition Temperature 3. D. Raftery, Philadelphia, PA;B.F. Chmelka, Santa Barbara, CA: Xenon NMR Spectroscopy 4. G. Fleischer, Leipzig, FRG; F. Fujara, Mainz, FRG: NMR as a Generalized Incoherent Scattering Experiment 5. P. Bl}mler, B. Bl}mich, Mainz, FRG: NMR Imaging of Solids

The present book is an attempt to outline some, certainly not all, mathematical aspects of modern organic chemistry. We have focused our attention on topological, graph-theoretical and group-theoretical features of organic chemistry, Parts A, B and C. The book is directed to all those chemists who use, or who intend to use mathe matics in their work, and especially to graduate students. The level of our exposition is adjusted to the mathematical background of graduate students of chemistry and only some knowledge of elementary algebra and calculus is required from the readers of the book. Some less well-known. but still elementary mathematical facts are collected in Appendices 1-4. This, however, does not mean that the mathematical rigor and numerous tedious, but necessary technical details have been avoided. The authors' intention was to show the reader not only how the results of mathematical chemistry look, but also how they can be obtained. In accordance with this, Part 0 of the book contains a few selected advanced topics which should give the reader the flavour of the contemporary research in mathe matical organic chemistry. One of the authors (I.G.) was an Alexander von Humboldt fellow in 1985 when the main part of the book was written. He gratefully acknowledges the financial support of the Alexander von Humboldt Foundation which enabled his stay at the Max-Planck-Institut fUr Strahlenchemie in M iilheim and the writing of this book."

During the last decade there has been a renewed interest in research on supramolecular assemblies in solutions, such as micelles and microemulsions, not only because of their extensive applications in industries dealing with catalysts, detergency, biotechnology, and enhanced oil recovery, but also due to the development of new and more powerful experimental and theoretical tools for probing the microscopic behavior of these systems. Prominent among the array of the newly available experimental techniques are photon correlation spectroscopy, small-angle neutron and X-ray scattering, and neutron spin-echo and nuclear magnetic resonance spectroscopies. On the theoretical side, the traditionally emphasized thermodynamic approach to the study of the phase behavior of self-assembled systems in solutions is gradually being replaced by statistical mechanical studies of semi-micro scopic and microscopic models of the assemblies. Since the statistical mechanical approach demands as its starting point the microscopic struc tural information of the self-assembled system, the experimental determina tion of the structures of micelles and microemulsions becomes of paramount interest. In this regard the scattering techniques mentioned above have played an important role in recent years and will continue to do so in the future. In applying the scattering techniques to the supramolecular species in solution, one cannot often regard the solution to be ideal. This is because the inter-aggregate interaction is often long-ranged since it is coulombic in nature and the interparticle correlations are thus appreciable."

This book contains the proceedings of the international workshop on Many-Atom Interactions in Solids, which was held June 5-9, 1989, in Pajulahti, Finland. The purpose of the workshop was to bring together physicists, chemists and materials scientists working in the field of interatomic interactions and their applications in computer simulations of condensed matter. The workshop attracted a good fraction of the active groups in the field, and created lively discussion and interchange of ideas. The contributions in this volume have been grouped by the editors into review type articles and more specific applications to different topics. The order of the articles does not follow the order of the presentations in the workshop. The editors wish to express their gratitude first of all to all the workshop par ticipants for creating an enjoyable and fruitful workshop and to the contributors for their efforts in putting together these proceedings. We hope that this volume will be a useful resource for practitioners in and newcomers to this exciting field. We would like to thank Jens N!l1rskov for his help in planning the scientific pro gramme and Eija Jarvinen for taking care of most of the practical arrangements of the workshop. The workshop was made possible by financial support from the Finnish Ministry of Education, the Research Institute for Theoretical Physics (Helsinki), NORDITA (Copenhagen), and Helsinki University of Technology.

The rivers run into the sea, yet the sea is not full Ecclesiastes What is quantum chemistry? The straightforward answer is that it is what quan tum chemists do. But it must be admitted, that in contrast to physicists and chemists, "quantum chemists" seem to be a rather ill-defined category of scientists. Quantum chemists are more or less physicists (basically theoreticians), more or less chemists, and by large, computationists. But first and foremost, we, quantum chemists, are conscious beings. We may safely guess that quantum chemistry was one of the first areas in the natural sciences to lie on the boundaries of many disciplines. We may certainly claim that quantum chemists were the first to use computers for really large scale calculations. The scope of the problems which quantum chemistry wishes to answer and which, by its unique nature, only quantum chemistry can only answer is growing daily. Retrospectively we may guess that many of those problems meet a daily need, or are say, technical in some sense. The rest are fundamental or conceptual. The daily life of most quantum chemists is usually filled with grasping the more or less technical problems. But it is at least as important to devote some time to the other kind of problems whose solution will open up new perspectives for both quantum chemistry itself and for the natural sciences in general.

Chemistry is the science of substances (today we would say molecules) and their transformations. Central to this science is the complexity of shape and function of its typical representatives. There lies, no longer dependent on its vitalistic antecedents, the rich realm of molecular possibility called organic chemistry. In this century we have learned how to determine the three-dimensional structure of molecules. Now chemistry as whole, and organic chemistry in particular, is poised to move to the exploration of its dynamic dimension, the busy business of transformations or reactions. Oh, it has been done all along, for what else is synthesis? What I mean is that the theoretical framework accom panying organic chemistry, long and fruitfully laboring on a quantum chemical understanding of structure, is now making the first tentative motions toward building an organic theory of reactivity. The Minkin, Simkin, Minyaev book takes us in that direction. It incorporates the lessons of frontier orbital theory and of Hartree-Fock SCF calculations; what chemical physicists have learned about trajectory calculations of selected reactions, and a simplified treatment of all-important solvent effects. It is written by professional, accomplished organic chemists for other organic chemists; it is consistently even-toned in its presentation of contending approaches. And very much up to date. That this contemporary work should emerge from a regional university in a country in which science has been highly centralized and organic chemistry not very modern, invites reflection."

so easy it seemed Once found, which yet unfound most would have thought Impossible. (John Milton, 1608 -1674) There are essentially two types of books on a scientific subject: in the first one several authors contribute their specialized approaches to parts of the field in question, which then are edited and compiled to yield a comprehensive and authoritative account. In the second type of book a single author tries to pre sent a view from an individual standpoint which might lead to a more balanced and homogeneous source of information. Both kinds have their merits and de ficiencies. I decided to write this book as a monolithic piece of work for several rea sons. Of course, there was the challenge of coping with the many problems of such an undertaking due to the fact that this field has grown tremendously during the last decades. In addition, being heavily involved in linear oligopyr role chemistry for nearly two decades, it seemed worthwile to prepare a more unifying approach. The request of several colleagues from abroad to give an account in English also triggered this endeavor since most of the work of my group has been published in German."

Understanding molecular orbitals (MOs) is a prerequisite to appreciating many physical and chemical properties of matter. This extensively revised second edition of A Pictorial Approach to Molecular Bonding presents the author's innovative approach to MOs, generating them pictorially for a wide variety of molecular geometries. A major enhancement to the second edition is the PC- and Macintosh-compatible Nodegame software, which is coordinated with the text and aids in pictorially teaching molecular orbital theory using generator orbitals.

Fundamentals of Continuum Mechanics of Soils provides a long-needed general scheme for the study of the important yet problematic material of soil. It closes the gap between two disciplines, soil mechanics and con- tinuum mechanics, showing that the familiar concepts of soil mechanics evolve directly from continuum mechanics. It confirms concepts such as pore pressures, cohesion and dependence of the shear stress on consolidation, and rejects the view that continuum mechanics cannot be applied to a material such as soil. The general concepts of continuum mechanics, field equations and constitutive equations are discussed. It is shown how the theory of mixtures evolves from these equations and how, along with energetics and irrevers- ible thermodynamics, it can be applied to soils. The discussion also sheds light on some aspects of mechanics of materials, especially compressible materials. Examples are the introduction of the Hencky measure of strain, the requirement of dual constitutive equations, and the dependence of the spent internal energy on the stored internal energy. Researchers in engineering mechanics and material sciences may find that the results of experiments on soils can be generalized and extended to other materials. The book is a reference text for students familiar with the fundamentals of mechanics, for scholars of soil engineering, and for soil scientists. It is also suitable as an advanced undergraduate course in soil mechanics.

The fifth volume in this series is focused on the chemical and physical interactions between rocks undergoing metamorphism and the fluids that they generate and that pass through them. The recognition that such pro cesses can profoundly affect the course of metamorphism has resulted in a number of recent papers and we consider that it is time for a review by some of the interested parties. We hope our selection of contributors provides an adequate cross section and demonstrates some of the flavor of this rapidly developing field. A cursory examination of the volume will reveal that there are widely divergent opinions on the compositions of metamorphic fluids and on the ways in which they interact physically and chemically with the rocks through which they pass. Since our own views are extensively discussed in Chapters 4 and 8, we leave the reader to determine his own brand of the "truth. " We wish to thank D. Bird, S. Bohlen, D. Carmichael, G. Flowers, C. Foster, C. Graham, E. Perry, J. Selverstone, R. Tracy, J. Valley, and R. Wollast for their chapter reviews. Thanks are also due C. Cheverton for her editorial assistance, and the helpful staff at Springer-Verlag New York."

The state-of-the-art in contemporary theoretical chemistry is presented in this 4-volume set with numerous contributions from the most highly regarded experts in their field. It provides a concise introduction and critical evaluation of theoretical approaches in relation to experimental evidence.

Solid-State NMR is a branch of Nuclear Magnetic Resonance which is presently experiencing a phase of strongly increasing popularity. The most striking evidence is the large number of contributions from Solid-State Resonance atNMR meetings, approaching that ofliquid state resonance. Important progress can be observed in three areas: Methodological developments, applications to inorganic matter, and applications to organic matter. These developments are intented to be captured in three volumes in this series, each of them being devoted to more or less one of these areas. The present volume on Solid-State NMR III is devoted mainly to organic matter. The recent developments of deuteron NMR and their applications are reviewed in the first chapter. Crosspolarization, MAS, and dynamic angle spinning are being explored for enhancement of information and sensitivity. In addition to the analysis of classical relaxation times and modern 2D spectra, detailed dynamic information becomes accessible from investigations of the relaxation time anisotropies. The second chapter examines cross-polarization in static and rotating solids under conditions of spin diffusion and thermal motion. The underlying dipole-dipole interaction is further exploited by the techniques described in the third chapter for studies of polymer-polymer miscibility. Short range techniques are discriminated from long-range techniques based on spin diffusion. The use ofthese techniques is illustrated by a case study ofPMMAJPVF blends. The last chapter addresses novel z methods and applications of two-dimensional exchange NMR for investigations of relative molecular orientations, polymer morphology, molecular dynamics, and macroscopic molecular order."

As a general rule any interdisciplinary subject and that includes Computational Theoretical Organic Chemistry (CTOC) incorporates people from the two overlaping areas. In this case the overlaping areas are Computational Theoretical Chemistry and Organic Chemistry. Since CTOC is a relatively young science, people continue to shift from their major discipline to this area. At this particular time in history we have to accept in CTOC people who were trained in Computational Theoretical Chemistry and do not know very much about Organic Chemistry, but more often the opposite case is operative Experimental Organic Chemistry who have not been exposed to Computational Theoretical Chemistry. This situation made NATO Advanced Study Institute in the field of CTOC necessary. The inhomogenity outlined above was present in the NATO Advanced Study Institute, held at Menton in July 1980, and to some degree it is noticable from the content of this volume. This book contains 20 contributions. The first contribution is an Introduc tion chapter in which the initiated experimental chemists are briefed about the subject matter. The last chapter describes very briefly the "Computational Laboratory" that was designed to help people with an experimental back ground in order to obtain some first hand experience. Between the first and the last chapters there are 18 contributions. These contributions were arranged in a spectrum from the exclusively method oriented papers to the applications of existing computational methods to problems of interest in Organic Chemistry."

Robert S. Mulliken, Nobel Laureate in chemistry, always had the intention to write a book about his field of research: molecular orbital theory. This is his scientific autobiography, edited posthumously by his former student Bernard J. Ransil and complemented with a memoir by Friedrich Hund, his scientific protagonist. Mulliken describes his career and gives an account of the contributions of his friends and colleagues at home and in Europe where he frequently travelled. And last but not least, he gives an accurate history of how the molecular orbital theory originated and how it evolved in an atmosphere of international exchange. The book is written in a particularly lively style, full of reminiscences and scientific facts, interwoven to produce an account of the Life of a Scientist.

The essential introduction to the understanding of the structure of inorganic solids and materials. This revised and updated 2nd Edition looks at new developments and research results within Structural Inorganic Chemistry in a number of ways, special attention is paid to crystalline solids, elucidation and description of the spatial order of atoms within a chemical compound. Structural principles of inorganic molecules and solids are described through traditional concepts, modern bond-theoretical theories, as well as taking symmetry as a leading principle.