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 n>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.

These two volumes collect thirty-eight selected papers from the scientific contributions presented at the Fourth European Workshop on Quantum Systems in Chemistry and Physics (QSCP-IV), held in Marly-le-Roi (France) in April 22-27, 1999. A total of one hundred and fifteen scientists attended the workshop, 99 from Europe and 16 from the rest of the world. They discussed the state of the art, new trends, and future evolution of the methods and applications. The workshop was held in the old town of Marly-le-Roi, which lies to the West of Paris between the historic centres of Saint-Germain-en-Laye and Versailles. Participants were housed at the National Youth Institute, where over sixty lectures were given by l- ding members of the scientific community; in addition, over sixty posters were presented in two very animated sessions. We are grateful to the oral speakers and to the poster p- senters for making the workshop such an stimulating experience. The social programme was also memorable - and not just for the closing banquet, which was held at the French Senate House. We are sure that participants will long remember their visit to the 'Musee des Antiquites Nationales' created by Napoleon III at the birthplace of Louis XIV, this museum boasts one of the world finest collections of archeological artifacts. The Marly-le-Roi workshop followed the format established at the three previous meetings, organized by Prof."

This book is meant to provide a window on the rapidly growing body of theoretical studies of condensed phase chemistry. A brief perusal of physical chemistry journals in the early to mid 1980's will find a large number of theor- ical papers devoted to 3-body gas phase chemical reaction dynamics. The recent history of theoretical chemistry has seen an explosion of progress in the devel- ment of methods to study similar properties of systems with Avogadro's number of particles. While the physical properties of condensed phase systems have long been principle targets of statistical mechanics, microscopic dynamic theories that start from detailed interaction potentials and build to first principles predictions of properties are now maturing at an extraordinary rate. The techniques in use range from classical studies of new Generalized Langevin Equations, semicl- sical studies for non-adiabatic chemical reactions in condensed phase, mixed quantum classical studies of biological systems, to fully quantum studies of m- els of condensed phase environments. These techniques have become sufficiently sophisticated, that theoretical prediction of behavior in actual condensed phase environments is now possible. and in some cases, theory is driving development in experiment. The authors and chapters in this book have been chosen to represent a wide variety in the current approaches to the theoretical chemistry of condensed phase systems. I have attempted a number of groupings of the chapters, but the - versity of the work always seems to frustrate entirely consistent grouping.

For the first time in the history of chemical sciences, theoretical predictions have achieved the level of reliability that allows them to - val experimental measurements in accuracy on a routine basis. Only a decade ago, such a statement would be valid only with severe qualifi- tions as high-level quantum-chemical calculations were feasible only for molecules composed of a few atoms. Improvements in both hardware performance and the level of sophistication of electronic structure me- ods have contributed equally to this impressive progress that has taken place only recently. The contemporary chemist interested in predicting thermochemical properties such as the standard enthalpy of formation has at his disposal a wide selection of theoretical approaches, differing in the range of app- cability, computational cost, and the expected accuracy. Ranging from high-level treatments of electron correlation used in conjunction with extrapolative schemes to semiempirical methods, these approaches have well-known advantages and shortcomings that determine their usefulness in studies of particular types of chemical species. The growing number of published computational schemes and their variants, testing sets, and performance statistics often makes it difficult for a scientist not well versed in the language of quantum theory to identify the method most adequate for his research needs.

This book describes mixed classical and quantum theories of dynamical processes with a particular emphasis on molecular Collisions. Purely quantum or purely classical approaches are inadequate for many systems.

Electron Correlations in Molecules and Solids bridges the gap between quantum chemistry and solid-state theory. In the first half of the text new concepts are developed for treating many-body and correlation effects, combining standard quantum chemical methods with projection techniques, Greens-function methods and Monte-Carlo techniques. The second half deals with applications of the theory to molecules, semiconductors, transition metals, heavy-fermion systems, and the new high-Tc superconducting materials.

Methods in Reaction Dynamics is a collection of lectures given at the 1999 Mariapfarr Workshop in Theoretical Chemistry. Arranged as a series of detailed reviews, it provides an overview of quantum mechanical techniques used to describe and simulate the dynamics and kinetics of elementary chemical reactions. The volume provides in-depth discussions of selected topics in Theoretical Chemistry, such as quantum methods in theoretical and computational reaction dynamics and kinetics; time-dependent, time-independent and mixed quantum-classical techniques. Some of the topics have not been reviewed before in detail.

For the New Century Issue of the journal "Theroretical Chemistry Accounts" the advisory editors identified papers from the first century of theoretical chemistry and discussed their importance for the twentieth century with an eye towards the twenty-first century. Sixty-six such perspectives are published in the New Century Issue. To make this unique collection available to younger scientists for entertaining reading and re-reading of the original publications, the publisher decided to reprint a special edition of the issue.

The goal of this volume is to bring together experts on numerical analysis, computer science and chemistry and produce homogenous contributions on ab initio quantum chemistry. The papers from the different communities collected in this volume are written in a language to be comprehensible to the others. This volume is of interest to applied mathematicians and quantum chemists.

This long-awaited and thoroughly updated version of the classic text (Plenum Press, 1970) explains the subject of electrochemistry in clear, straightforward language for undergraduates and mature scientists who want to understand solutions. Like its predecessor, the new text presents the electrochemistry of solutions at the molecular level. The Second Edition takes full advantage of the advances in microscopy, computing power, and industrial applications in the quarter century since the publication of the First Edition. Such new techniques include scanning-tunneling microscopy, which enables us to see atoms on electrodes; and new computers capable of molecular dynamics calculations that are used in arriving at experimental values. A description of the electrochemical stage - the high field region near the interface - is the topic of Chapter 6 and involves a complete rewrite of the corresponding chapter in the First Edition, particularly the various happenings which occur with organic molecules which approach surfaces in solution. The chapter on electrode kinetics retains material describing the Butler-Volmer equation from the First Edition, but then turns to many new areas, including electrochemical theories of potential-dependent gas catalysis. Chapter 8 is a new one devoted to explaining how electrochemists deal with the fast-changing nature of the electrode surface. Quantum Mechanics as the basis to electrode kinetics is given an entirely new look - up to and including considerations of bond-breaking reactions.

The authors demonstrate that the essential information about order in, and energy levels of physical systems is encapsulated in the second order reduced density matrix. They have discovered an algorithm to obtain a reasonable accurate expression for the 2-matrix of an N-particle state to make nearly all properties of matter which are of interest to chemists and physicists accessible.

André Julg has published several papers concerning the continuity of classical physics and quantum mechanics. He provides a provocative conclusion in this book: the quantum formalism can be effectively interpreted within the framework of classical physics, provided some minor rearrangements are accepted.

The linear Schrodinger equation is central to Quantum Chemistry. It is presented within the context of relativistic Quantum Mechanics and analysed both in time-dependent and time-independent forms. The Riccati equation is used to study the one-dimensional Schrodinger equation.
The authors develop the Schrodinger-Riccati equation as an approach to determine solutions of the time-independent, linear Schrodinger equation."

For chemists, biochemists, physicists and materials scientists, pressure as an experimental variable represents a tool that provides unique information about the microscopic properties of the materials being studied. In addition to its use as a research tool for investigating the energetics, structure, dynamics and kinetics of molecular transformations of materials, pressure is also being used to modify the properties of materials to preserve or improve their properties. The contributions collected here cover the main areas of high pressure research, including applications in materials science, condensed matter physics, chemistry and biochemistry. In addition, some papers offer more specialised aspects of high pressure studies. The book makes clear the impressive range of fundamental and applied problems that can be studied by high pressure techniques and also points towards a major growth of high pressure science and technology in the near future.

The main subjects are:
- a comprehensive mathematical description of molecular systems,
- a new reaction path concept,
- an algorithm for following the reaction path.
The reaction path's tangent is determined by an excitation vector and the saddle points surrounding a minimizer can be localized without further information. A procedure appropriate to trace these reaction paths is presented.

This textbook presents basic and advanced computational physics in a very didactic style. It contains very-well-presented and simple mathematical descriptions of many of the most important algorithms used in computational physics. The first part of the book discusses the basic numerical methods. The second part concentrates on simulation of classical and quantum systems. Several classes of integration methods are discussed including not only the standard Euler and Runge Kutta method but also multi-step methods and the class of Verlet methods, which is introduced by studying the motion in Liouville space. A general chapter on the numerical treatment of differential equations provides methods of finite differences, finite volumes, finite elements and boundary elements together with spectral methods and weighted residual based methods. The book gives simple but non trivial examples from a broad range of physical topics trying to give the reader insight into not only the numerical treatment but also simulated problems. Different methods are compared with regard to their stability and efficiency. The exercises in the book are realised as computer experiments.

The development of computational methods that support human health and environmental risk assessment of engineered nanomaterials (ENMs) has attracted great interest because the application of these methods enables us to fill existing experimental data gaps. However, considering the high degree of complexity and multifunctionality of ENMs, computational methods originally developed for regular chemicals cannot always be applied explicitly in nanotoxicology. This book discusses the current state of the art and future needs in the development of computational modeling techniques for nanotoxicology. It focuses on (i) computational chemistry (quantum mechanics, semi-empirical methods, density functional theory, molecular mechanics, molecular dynamics), (ii) nanochemoinformatic methods (quantitative structure-activity relationship modeling, grouping, read-across), and (iii) nanobioinformatic methods (genomics, transcriptomics, proteomics, metabolomics). It reviews methods of calculating molecular descriptors sufficient to characterize the structure of nanoparticles, specifies recent trends in the validation of computational methods, and discusses ways to cope with the uncertainty of predictions. In addition, it highlights the status quo and further challenges in the application of computational methods in regulation (e.g., REACH, OECD) and in industry for product development and optimization and the future directions for increasing acceptance of computational modeling for nanotoxicology.

A number of general-purpose, reasonably accurate and well-tested ab-initio codes for crystals are discussed in this book. The aim is to expand competence of their application in material sciences and solid-state physics. The book addresses particularly readers with a general knowledge in quantum chemistry and intends to give a deeper insight into the special algorithms and computational techniques in ab-initio computer codes for crystals. Three different programs which are available to all interested potential users on request are presented.

In simple language, without mathematics, this book explains the strange and exciting ideas that make the subatomic world so different from the world of the every day. It offers the general reader access to one of the greatest discoveries in the history of physics and one of the oustanding intellectual achievements of the twentieth century.

The application of neutron scattering to polymers has been extremely successful during the last two decades. This book presents, for the first time, both the theories and experimental examples which are needed to understand how these techniques can be applied. Now available in paperback for the first time this book is specifically written to introduce the newcomer and non-expert to the experimental techniques and the basic theory necessary to understand the results.

This book covers important new developments of the last five years in the area of cluster chemistry, presenting an excellent view of the successes and shortcomings of both current state-of-the-art theory and experiment. Each chapter, contributed by a leading expert, places heavy emphasis on theory without which the detailed analysis of the spectroscopic and kinetic results would be compromised. The cluster reactions reviewed in this work include electron and proton transfer reactions, hot atom reactions, vibrational predissociation, radical reactions, and ionic reactions. Some of the theories applied throughout the text are product state distribution determinations, state-to-state dynamical information, and access to the transition stage of the reaction. The discussions serve as a benchmark of how far the field has come since the mid 1980's and will be a good update for students and researchers interested in this area of physical chemistry.

The first volume of Lecture Notes in Quantum Chemistry (Lecture Notes in Chemistry 58, Springer Verlag, Berlin 1992) contained a compilation of selected lectures given at the two first European Summer Schools in Quantum Chemistry (ESQC), held in southern Sweden in August 1989 and 1991, respectively. The notes were written by the teachers at the school and covered a large range of topics in ab initio quantum chemistry. After the third summer school (held in 1993) it was decided to put together a second volume with additional material. Important lecture material was excluded in the first volume and has now been added. Such added topics are: integrals and integral derivatives, SCF theory, coupled-cluster theory, relativity in quantum chemistry, and density functional theory. One chapter in the present volume contains the exercise material used at the summer school and in addition solutions to all the exercises. It is the hope of the authors that the two volumes will find good use in the scientific community as textbooks for students, who are interested in learn ing more about modern methodology in molecular quantum chemistry. The books will be used as teaching material in the European Summer Schools in Quantum Chemistry, which are presently planned. Lund in July 1994 Bjorn Roos NOTES ON HARTREE-FOCK THEORY AND RELATED TOPICS JanAlmlof Department of Chemistry University of Minnesota Minneapolis, MN 55455. USA Contents: 1 * Introduction. 2 . The Born-Oppenheimer Approximation. 3. Determinant Wavefunctions and the Pauli Principle. 4. Expectation Values With a Determinant Wavefunction.

Ideas of Quantum Chemistry, Volume One: From Quantum Physics to Chemistry shows how quantum mechanics is applied to molecular sciences to provide a theoretical foundation. Organized into digestible sections and written in an accessible style, it answers questions, highlighting the most important conclusions and essential mathematical formulae. Beginning with an introduction to the magic of quantum mechanics, the book goes on to review such key topics as the Schroedinger Equation, exact solutions, and fundamental approximate methods. The crucial concept of molecular shape is then discussed, followed by the motion of nuclei and the orbital model of electronic structure. This updated volume covers the latest developments in the field and can be used either on its own as a detailed introduction to quantum chemistry or in combination with Volume Two to give a complete overview of the field.

This book provides an introduction to the use of algebraic methods and sym bolic computation for simple quantum systems with applications to large order perturbation theory. It is the first book to integrate Lie algebras, algebraic perturbation theory and symbolic computation in a form suitable for students and researchers in theoretical and computational chemistry and is conveniently divided into two parts. The first part, Chapters 1 to 6, provides a pedagogical introduction to the important Lie algebras so(3), so(2,1), so(4) and so(4,2) needed for the study of simple quantum systems such as the D-dimensional hydrogen atom and harmonic oscillator. This material is suitable for advanced undergraduate and beginning graduate students. Of particular importance is the use of so(2,1) in Chapter 4 as a spectrum generating algebra for several important systems such as the non-relativistic hydrogen atom and the relativistic Klein-Gordon and Dirac equations. This approach provides an interesting and important alternative to the usual textbook approach using series solutions of differential equations."

Chemical bonds, their intrinsic energies in ground-state molecules and the energies required for their actual cleavage are the subject of this book. The theory, modelled after a description of valence electrons in isolated atoms, explains how intrinsic bond energies depend on the amount of electronic charge carried by the bond-forming atoms. It also explains how bond dissociation depends on these charges. While this theory vividly explains thermochemical stability, future research could benefit from a better understanding of bond dissociation: if we learn how the environment of a molecule affects its charges, we also learn how it modifies bond dissociation in that molecule. This essay is aimed at theoretical and physical-organic chemists who are looking for new perspectives to old problems.