The NATO Advanced Study Institute (ASI) on "Relativistic Effects in Atoms, Molecules and Solids" cosponsored by Simon Fraser University (SFU) and Natural Sciences and Engineering Research Council of Canada (NSERC) was held at the University of British Columbia (UBC) , Van couver, Canada from August 10th until August 21st, 1981. A total of 77 lecturers and students with diverse backgrounds in Chemistry, Physics, Mathematics and various interdisciplinary subjects attended the ASI. In the proposal submitted to NATO for financial support for this ASI, it was suggested that recent impressive experimental developments coupled with the availability of sophisticated computer technology for detailed investigation of the relativistic structure of atoms, molecules and solids would provide an excellent testing ground for the validity and accuracy of the theoretical treatment of the rela tivistic many-electron systems involving medium and heavy atoms. Such systems are also of interest to the current energy crisis because of their usage for photovoltaic devices, nuclear fuels (UF6), fusion lasers (Xe*2)' catalysts for solar energy conversion, etc.

Recent years have seen a growing interest in the effects of relativity in atoms, molecules and solids. On the one hand, this can be seen as result of the growing awareness of the importance of relativity in describing the properties of heavy atoms and systems containing them. This has been fueled by the inadequacy of physical models which either neglect relativity or which treat it as a small perturbation. On the other hand, it is dependent upon the technological developments which have resulted in computers powerful enough to make calculations on heavy atoms and on systems containing heavy atoms meaningful. Vector processing and, more recently, parallel processing techniques are playing an increasingly vital role in rendering the algorithms which arise in relativistic studies tractable. This has been exemplified in atomic structure theory, where the dominant role of the central nuclear charge simplifies the problem enough to permit some prediction to be made with high precision, especially for the highly ionized atoms of importance in plasma physics and in laser confinement studies. Today's sophisticated physical models of the atom derived from quantum electrodynamics would be intractable without recourse to modern computational machinery. Relativistic atomic structure calculations have a history dating from the early attempts of Swirles in the mid 1930's but continue to provide one of the primary test beds of modern theoretical physics.

Heavy atoms and their compounds are important in many areas of modern technology. Their versatility in the reactions they undergo is the reason that they can be found in most homogeneous and heterogeneous catalysts. Their magnetism is the decisive property that qualifies them as materials for modern storage devices. The phenomena observed in compounds of heavy atoms such as phosphorescence, magnetism or the tendency for high valency in chemical reactions can to a large extent be traced back to relativistic effects in their electronic structure. Thus, in many respects relativistic effects dominate the physics and chemistry of heavy atoms and their compounds. Chemists are usually aware of these phenomena. However, the theory behind them is not part of the standard chemistry curriculum and thus not widely known among experimentalists. Whilst the relativistic quantum theory of electronic structure is well established in physics, applications of the theory to chemical systems and materials have been feasible only in the last decade and their practical applications in connection with chemical experiment is somewhat out of sight of modern theoretical physics. Relativistic Effects in Heavy Element Chemistry and Physics intends to bridge the gap between chemistry and physics on the one hand and theory and experiment on the other. Topics covered include: - A broad range from quantum electrodynamics to the phenomenology of the compounds of heavy and superheavy elements; - A state-of-the-art survey of the most important theoretical developments and applications in the field of relativistic effects in heavy-element chemistry and physics in the last decade; - Special emphasis on the work of researchers in Europe and Germany in the framework of research programmes of the European Science Foundation and the German Science Foundation.

This book is intended for physicists and chemists who need to understand the theory of atomic and molecular structure and processes, and who wish to apply the theory to practical problems. As far as practicable, the book provides a self-contained account of the theory of relativistic atomic and molecular structure, based on the accepted formalism of bound-state Quantum Electrodynamics. The author was elected a Fellow of the Royal Society of London in 1992.

Relativistic effects are of major importance for understan- ding the properties of heavier atoms and molecules. This book is still the only comprehensive bibliography on related calculations. The material is organized by subject into ta- bles containing a concise characterization. Together with Volume I (Lecture Notes in Chemistry Vol. 41, ISBN 3-540-17167-3) the literature until 1992 is now covered and 6577 references, with titles, are given in the two books. The book will provide aconvenient reference for theoretical chemists and atomic and molecular physicists interested in the properties of heavier elements. Contents: Introduction - One-particle problems - Quantum electrodynamical effects - Multielectron atoms: methods - Multielectron atoms: results - Symmetry - Molecular calcula- tions - Solid-state theory - Relativistic effects and heavy- element chemistry - Corrections to Volume I - Some comments on notations and terminology - List of acronyms and symbols - Bibliography.

Quantum mechanics provides the fundamental theoretical apparatus for describing the structure and properties of atoms and molecules in terms of the behaviour of their fundamental components, electrons and nudeL For heavy atoms and molecules containing them, the electrons can move at speeds which represent a substantial fraction of the speed of light, and thus relativity must be taken into account. Relativistic quantum mechanics therefore provides the basic formalism for calculating the properties of heavy-atom systems. The purpose of this book is to provide a detailed description of the application of relativistic quantum mechanics to the many-body prob lem in the theoretical chemistry and physics of heavy and superheavy elements. Recent years have witnessed a continued and growing interest in relativistic quantum chemical methods and the associated computa tional algorithms which facilitate their application. This interest is fu elled by the need to develop robust, yet efficient theoretical approaches, together with efficient algorithms, which can be applied to atoms in the lower part of the Periodic Table and, more particularly, molecules and molecular entities containing such atoms. Such relativistic theories and computational algorithms are an essential ingredient for the description of heavy element chemistry, becoming even more important in the case of superheavy elements. They are destined to become an indispensable tool in the quantum chemist's armoury. Indeed, since relativity influences the structure of every atom in the Periodic Table, relativistic molecular structure methods may replace in many applications the non-relativistic techniques widely used in contemporary research.

This book provides an introduction to the essentials of relativistic effects in quantum chemistry, and a reference work that collects all the major developments in this field. It is designed for the graduate student and the computational chemist with a good background in nonrelativistic theory. In addition to explaining the necessary theory in detail, at a level that the non-expert and the student should readily be able to follow, the book discusses the implementation of the theory and practicalities of its use in calculations. After a brief introduction to classical relativity and electromagnetism, the Dirac equation is presented, and its symmetry, atomic solutions, and interpretation are explored. Four-component molecular methods are then developed: self-consistent field theory and the use of basis sets, double-group and time-reversal symmetry, correlation methods, molecular properties, and an overview of relativistic density functional theory. The emphases in this section are on the basics of relativistic theory and how relativistic theory differs from nonrelativistic theory. Approximate methods are treated next, starting with spin separation in the Dirac equation, and proceeding to the Foldy-Wouthuysen, Douglas-Kroll, and related transformations, Breit-Pauli and direct perturbation theory, regular approximations, matrix approximations, and pseudopotential and model potential methods. For each of these approximations, one-electron operators and many-electron methods are developed, spin-free and spin-orbit operators are presented, and the calculation of electric and magnetic properties is discussed. The treatment of spin-orbit effects with correlation rounds off the presentation of approximate methods. The book concludes with a discussion of the qualitative changes in the picture of structure and bonding that arise from the inclusion of relativity.