A comprehensive review of ion beam application in modern materials research is provided, including the basics of ion beam physics and technology. The physics of ion-solid interactions for ion implantation, ion beam synthesis, sputtering and nano-patterning is treated in detail. Its applications in materials research, development and analysis, developments of special techniques and interaction mechanisms of ion beams with solid state matter result in the optimization of new material properties, which are discussed thoroughly. Solid-state properties optimization for functional materials such as doped semiconductors and metal layers for nano-electronics, metal alloys, and nano-patterned surfaces is demonstrated. The ion beam is an important tool for both materials processing and analysis. Researchers engaged in solid-state physics and materials research, engineers and technologists in the field of modern functional materials will welcome this text.

The origin of optical methods for fluid flow investigations appears to be nontraceable. This is no matter for surprise. After all seeing provides the most direct and common way for humans to learn about their environment. But at the same time some of the most sophisticated methods for doing measurements in fluids are also based on light and often laser light. A very large amount of material has been published in this area over the last two decades. Why then another publication? Well, the field is still in a state of rapid development. It is characterised by the use of results and methods developed within very different areas like optical physics, spectroscopy, communication systems, electronics and computer science, mechanical engineering, chemical engineering and, of course, fluid dynamics. We are not aware of a book containing both introductory and more advanced material that covers the same material as presented here. The book is the result of a compilation and expansion of material presented at a summer school on Optical Diagnosticsfor Flow Processes, held at RiS0 National Laboratory and the Technical University of Denmark in September 1993. The aim of the course was to provide a solid background for understanding, evaluating, and using modem optical diagnostic methods, addressing Ph. D. students and researchers active in areas of fluid flow research. The disciplines represented by the participants ranged from atmospheric fluid dynamics to biomedicine

Nature is characterized by a number of physical laws and fundamental dimensionless couplings. These determine the properties of our physical universe, from the size of atoms, cells and mountains to the ultimate fate of the universe as a whole. Yet it is rather remarkable how little we know about them. The constancy of physical laws is one of the cornerstones of the scientific research method, but for fundamental couplings this is an assumption with no other justification than a historical assumption. There is no 'theory of constants' describing their role in the underlying theories and how they relate to one another or how many of them are truly fundamental. Studying the behaviour of these quantities throughout the history of the universe is an effective way to probe fundamental physics. This explains why the ESA and ESO include varying fundamental constants among their key science drivers for the next generation of facilities. This symposium discussed the state-of-the-art in the field, as well as the key developments anticipated for the coming years.

Interferometry, the most precise measurement technique known today, exploits the wave-like nature of the atoms or photons in the interferometer. As expected from the laws of quantum mechanics, the granular, particle-like features of the individually independent atoms or photons are responsible for the precision limit, the shot noise limit. However this "classical" bound is not fundamental and it is the aim of quantum metrology to overcome it by employing entanglement among the particles. This work reports on the realization of spin-squeezed states suitable for atom interferometry. Spin squeezing was generated on the basis of motional and spin degrees of freedom, whereby the latter allowed the implementation of a full interferometer with quantum-enhanced precision.

The aim of the workshop was to bring together specialists in various fields where non-exponential relaxation is observed in order to compare models and experimental results and to examine the general physical principles governing this type of behaviour. Non-exponential relaxation is found in extremely diverse physical systems all of which can be classified as complex. The form of the relaxation is generally parametrized using logarithmic, algebraic or stretched exponential decay forms. The conceptually simplest mechanism for the non-exponential decay is a spectrum of relaxation rates due to non-interacting units each of which relaxes with a different intrinsic time constant. Clear experimental examples can be given where for instance the relaxation of a collection of isolated polymer molecules leads to an overall stretched exponential decay. Non-exponential relaxation is observed in all strongly interacting complex systems (structural glasses, spin glasses, etc ... ) where each elementary unit is in interaction with many other units.

The book addresses graduate students as well as scientists interested in applications of the standard model for strong and electroweak interactions to experimentally determinable quantities. Computer simulations and the relations between various approaches to quantum field theory, such as perturbative methods, lattice methods and effective theories, are also discussed.

At this Obergurgl seminar, theoreticians and experimentalists discussed recent developments in laser interactions. This volume contains the texts of invited lectures and abstracts of contributed papers. The main topics discussed are: * multiphoton ionization * above-threshold ionization * collisions in strong fields * atoms in intense fields * chaos in radiative interactions * electron correlations in multiphoton processes * Rydberg atoms in external fields * other laser interactions. Thus a broad and up-to-date account of laser interactions is given which will be of interest to scientists, engineers and graduate students.

The Rationale for the Present Book Perhaps the most critical problem facing present-day particle physicistsis to delineate the relationship between classical and quantum systems. This relationship has many facets. Particle-waveduality is one. The concept of the point particle is another. And theconcept of particle mass is yet another. The electron, as the lightest of the charged particles, represents a fundamental "ground state,"and many of the essential problems in the murky area between the domainsofclassical and quantum physics can be brought into focus by studyingjust this one particle. Thus the present book is centered on questions that arise in connection with the electron, and in particular with its mass, which has remained an unsolved, and indeed almost unexplored, mystery. Each student ofphysics, beginner and professional alike, has to fashion for himselfa way of thinking about the electron. If, after reading this book, the reader views this topic somewhat differently than before, the efforts of the author will have been amply rewarded. When physicists were confronted with the properties of the electron, they made a conceptualleap into the unknown: they concluded that the electron does not obey classical laws with respect to mechanics (as connected to the spin of the electron), and also with respect to electrodynamics (as connected to the magnetic moment of the electron).

Colloidal dispersions play a very important role in nature, industry, and daily life. Sometimes, long-term stability is observed or desired as in ferrotluids (composed of very small magnetic particles with radii of ~ 10 nm), which must be stable even in external fields. On the other hand, only short-term stable dispersions may be necessary during actual processing operations, for example, dispersions of magnetite particles during tape manufacture. The stability of dispersions and many of their physical properties are related to the interaction between the particles in the dispersion medium, which may contain surfactants or macromolecular species. If the net interparticle interaction forces are attractive, then aggregation may occur. Two general types of aggregation behavior may be distinguished: coagulation and flocculation. These two terms are frequently used synonymously but IUPAC has recommended the following definitions: Coagulation implies formation of compact aggregates, leading to the macroscopic separation. Flocculation implies the formation of a loose or open network, floc, which may or may not separate macroscopically. Flocculation brought about by the simultaneous coadsorption of polymer molecules on two (or more) particles is referred to as bridging flocculation. If coagulation results in the merging of two particles into one, as may occur with liquid droplets in emulsions, this process is referred to as coalescence.

This book had its origins in lectures presented at EPFL, Lausanne, during two separate visits (the most recent being to IRRMA). The author is most grateful to Professors A. Baldereschi, R. Car, and A. Quattropani for making these visits possible, and for the splendidly stimulating environment provided. Professors S. Baroni and R. Resta also influenced considerably the presentation of material by constructive help and comments. Most importantly, Chapters 4 and 5 were originally prepared for a review article by Professor G. Senatore, then at Pavia and now in Trieste, and myself for Reviews of Modem Physics (1994). In the 'course of this collaboration, he has taught me a great deal, especially about quantum Monte Carlo procedures, and Chapter 5 is based directly on this review article. Also in Chapter 4, my original draft on Gutzwiller's method has been transformed by his deeper understanding; again this is reflected directly in Chapter 4; especially in the earlier sections. In addition to the above background, it is relevant here to point out that, as a backcloth for the present, largely "state of the art," account, there are two highly relevant earlier books: The Many-body Problem in Quantum Mechanics with W.

The theory of the inhomogeneous electron gas had its origin in the Thomas Fermi statistical theory, which is discussed in the first chapter of this book. This already leads to significant physical results for the binding energies of atomic ions, though because it leaves out shell structure the results of such a theory cannot reflect the richness of the Periodic Table. Therefore, for a long time, the earlier method proposed by Hartree, in which each electron is assigned its own personal wave function and energy, dominated atomic theory. The extension of the Hartree theory by Fock, to include exchange, had its parallel in the density description when Dirac showed how to incorporate exchange in the Thomas-Fermi theory. Considerably later, in 1951, Slater, in an important paper, showed how a result similar to but not identical with that of Dirac followed as a simplification of the Hartree-Fock method. It was Gombas and other workers who recognized that one could also incorporate electron correlation consistently into the Thomas-Fermi-Dirac theory by using uniform electron gas relations locally, and progress had been made along all these avenues by the 1950s."

In the slightly more than thirty years since its formulation, the Hubbard model has become a central component of modern many-body physics. It provides a paradigm for strongly correlated, interacting electronic systems and offers insights not only into the general underlying mathematical structure of many-body systems but also into the experimental behavior of many novel electronic materials. In condensed matter physics, the Hubbard model represents the simplest theoret ical framework for describing interacting electrons in a crystal lattice. Containing only two explicit parameters - the ratio ("Ujt") between the Coulomb repulsion and the kinetic energy of the electrons, and the filling (p) of the available electronic band - and one implicit parameter - the structure of the underlying lattice - it appears nonetheless capable of capturing behavior ranging from metallic to insulating and from magnetism to superconductivity. Introduced originally as a model of magnetism of transition met als, the Hubbard model has seen a spectacular recent renaissance in connection with possible applications to high-Tc superconductivity, for which particular emphasis has been placed on the phase diagram of the two-dimensional variant of the model. In mathematical physics, the Hubbard model has also had an essential role. The solution by Lieb and Wu of the one-dimensional Hubbard model by Bethe Ansatz provided the stimulus for a broad and continuing effort to study "solvable" many-body models. In higher dimensions, there have been important but isolated exact results (e. g., N agoaka's Theorem)."

This volume contains the invited papers and selected contributed papers presented at the biennial International Symposium on ELECTRON COLLISIONS WITH MOLECULES, CLUSTERS AND SURF ACES held at Royal Holloway, University of London from 29th to 30th July, 1993. This Symposium was a Satellite Meeting of the XVIII International Conference on the Physics of Electronic and Atomic Collisions (ICPEAC) and follows a 16 year tradition of Satellite Conferences in related areas of collisions held in association with previous ICPEAC's. In the past each of these electron -molecule symposia covered the broad field of electron-molecule scattering at rather low energies, but also included hot topics. This time as well as covering the whole field, well defined electron collisions with clusters and with particles in the complex potential of a surface were emphasized. Not many details are known about such collisions, although they become more and more important in surface characterisation, plasma-wall interactions, electron induced desorption and reorganisation of adsorbed particles. Recently, much work, theoretical and experimental, has been devoted to electron collisions with rather large carbon, silicon and halogen containing molecules. These problems are of relevance in plasma assisted thin film formation and etching of surfaces and can now be approached with advanced theoretical methods and experimental equipment.

The Nato Advanced Study Institute "Phase Transitions in Liquid Crystals" was held May 2-12, 1991, in Erice, Sicily. This was the 16th conference organized by the International School of Quantum Electronics, under the auspices of the "Ettore Majorana" Centre for Scientific Culture. The subject of "Liquid Crystals" has made amazing progress since the last ISQE Course on this subject in 1985. The present Proceedings give a tutorial introduction to today's most important areas, as well as a review of current results by leading researchers. We have brought together some of the world's acknowledged experts in the field to summarize both the present state of their research and its background. Most of the lecturers attended all the lectures and devoted their spare hours to stimulating discussions. We would like to thank them all for their admirable contributions. The Institute also took advantage of a very active audience; most of the students were active researchers in the field and contributed with discussions and seminars. Some of these student seminars are also included in these Proceedings. We did not modify the original manuscripts in editing this book, but we did group them according to the following topics: 1) "Theoretical Foundations"; 2) "Thermotropic Liquid Crystals"; 3) "Ferroelectric Liquid Crystals"; 4) "Polymeric Liquid Crystals"; and 5) "Lyotropic Liquid Crystals".

For more than a century, studies of atomic hydrogen have been a rich source of scientific discoveries. These began with the Balmer series in 1885 and the early quantum theories of the atom, and later included the development of QED and the first successful gauge field theory. Today, hydrogen and its relatives continue to provide new fundamental information, as witnessed by the contributions to this book. The printed volume contains invited reviews on the spectroscopy of hydrogen, muonium, positronium, few-electron ions and exotic atoms, together with related topics such as frequency metrology and the determination of fundamental constants. The accompanying CD contains, in addition to these reviews, a further 40 contributed papers also presented at the conference "Hydrogen Atom 2" held in summer 2000. Finally, to facilitate a historical comparison, the CD also contains the proceedings of the first "Hydrogen Atom" conference of 1988. The book includes a foreword by Norman F. Ramsey.

These proceedings give fundamental information on the collision mechanisms of ions and atoms at relatively high energies and on their highly excited atomic states. The information derived from such studies can often be applied in other fields such as material analysis, dosimetry, the study of the upper atmosphere and controlled fusion. Phenomena involving the classical ion-atom collision fields, impact parameter dependences, quasimolecular and electron correlation effects, coherence phenomena, the electron and photon spectroscopy of highly charged projectile and recoil ions, the loss and capture of electrons, molecular and solid state effects, and different aspects of instrumentation are all discussed in this volume.

This volume represents the fIrst of a series of proceedings of the EL.B.A. Forum on Bioelectronics, a scientifIc discipline at the frontiers of Advanced Electronics and Biotechnology. The name for these forums derives not only from the place (the Isle of Elba in Italy), where the conferences have been held every 6 months since 1991, but also from an acronym: Electronics and Biotechnology Advanced. Bioelectronics is intended as "the use of biological materials and biological architectures for information processing and sensing systems and devices down to molecular level" and focuses its attention on three major areas: I New hardware architectures borrowed from the thorough study of brain and sensory systems down to the molecular level, utilizing existing semiconductor inorganic materials (both GaAs and Si) and giga-scale integration; II Protein Engineering, especially of systems involved in electron transfer and molecular recognition, integrated with Metabolism and Chemical Engineering, to develop new biomaterials by learning basic rules of macromolecular folding and self-assembly; m Sensors, thin film and electronic devices utilizing organic compounds and biopolymers, and by implementing nanotechnology bottom up through manufacturing and characterization at the atomic level.

of available information. Even more importantly, some authors who have contributed substantially to an area may have been overlooked. For this I apologize. I have, however, not attempted to trace techniques or observa tions historically, so there is no implication (unless specified) that the authors referred to were or were not the originators of a given method or observation. I would like to acknowledge discussions with co-workers at SFU for input relative to their specialties, to acknowledge the help of students who have pointed out errors and difficulties in the earlier presentation, and to acknowledge the infinite patience of my wife Phyllis while I spent my sabbatical and more in libraries and punching computers. S. Roy Morrison 0 1 Contents Notation XV 1. Introduction 1 1. 1. Surface States and Surface Sites . 1 1. 1. 1. The Chemical versus Electronic Representation of the Surface. 1 1. 1. 2. The Surface State on the Band Diagram 4 1. 1. 3. The Fermi Energy in the Surface State Model. 6 1. 1. 4. Need for Both Surface Site and Surface State Models 6 1. 2. Bonding of Foreign Species to the Solid Surface 7 1. 2. 1. Types of Interaction. 7 1. 2. 2. The Chemical Bond . 10 1. 2. 3. Acid and Basic Surface Sites on Solids . 13 1. 2. 4. Adsorbate Bonding on Various Solid Types. 16 1. 2. 5. Movement of Surface Atoms: Relaxation, Reconstruction, and Relocation ."

This book has been written as part of a series of scientific books being published by Plenum Press. The scope of the series is to review a chosen topic in each volume. To supplement this information, the abstracts to the most important references cited in the text are reprinted, thus allowing the reader to find in-depth material without having to refer to many additional publications. This volume is dedicated to the field of dry (plasma) etching, as applied in silicon semiconductor processing. Although a number of books have appeared dealing with this area of physics and chemistry, these all deal with parts of the field. This book is unique in that it gives a compact, yet complete, in-depth overview of fundamentals, systems, processes, tools, and applications of etching with gas plasmas for VLSI. Examples are given throughout the fundamental sections, in order to give the reader a better insight in the meaning and magnitude of the many parameters relevant to dry etching. Electrical engineering concepts are emphasized to explain the pros and cons of reactor concepts and excitation frequency ranges. In the description of practical applications, extensive use is made of cross-referencing between processes and materials, as well as theory and practice. It is thus intended to provide a total model for understanding dry etching. The book has been written such that no previous knowledge of the subject is required. It is intended as a review of all aspects of dry etching for silicon semiconductor processing.

Following the first Capri School on Photon Correlation Spectroscopy held in July 1973 and published earlier in this series (Series B: Physics v.3) a second Capri NATO Advanced Study Institute on this topic was held at the Hotei Luna from 26 July to 6 August 1976. This volume contains the invited lecture courses and seminars and some of the contributed seminars presented at this Institute. Much had happened in the field in the intervening three years and it was the intention of the Organising Committee to build on the previous courses * without detailed repetition of fundamentals. and to extend the coverage widely over the use of photon-correla tion methods for the temporal or spectral analysis of fluctuating light sources. In particular, the rapid expansion of these methods for the measurement of macroscopic motion by Laser Doppler Veloci metry was given special emphasis as is indicated in the title. The members of the Organizing Committee were: E R Pike, RSRE, Malvern, UK } _ Co-directors H Z Cummins, CCNY, New York, USA M Bertolotti, University of Rome, Italy - Local Organiser P Pusey, RSRE, Malvern, UK - Treasurer V DeGiorgio, CISE, Milan, Italy P Lallemand, ENS, Paris, France Pierre de Gennes assisted the Committee during the planning of the Institute but was unfortunately prevented at the last minute from attending.

This volume contains the invited contributions to the NATO Advanced Research Workshop on Integrable Quantum Field Theories held at the Villa Olmo, Como, Italy, September 14-18, 1992. About 70 researchers from all over world gathered at this in- terdisciplinary workshop, which turned out to be timely and very stimulating. We are grateful to the institutions that made it possible: the NATO Scientific Affairs Divi- sion, the Istituto Nazionale di Fisica Nucleare and the Scuola Internazionale Superiore di Studi Avanzati for financial support, and the Centro A.Volta for hospitality. In the past decades integrability was mostly explored in the framework of mathe- matical physics. However, in the last few years it has become a prominent subject in many domains of theoretical physics: two dimensional statistical mechanical models, two-dimensional conformal field theories and their perturbations, matrix models of two-dimensional gravity. This trend has been confirmed by the workshop: progress has been reported in all of the above topics both from physicists and mathematicians. One can recognize three broad groups of subjects: 1) 2D lattice models and off-critical solvable models, 2) Kac-Moody algebras and their role in integrable theories, 3) matrix models of string theory and their relation with topological and integrable field theories.

The NATO Advanced Study Institute on "Atomic and Molecular Processes in Controlled TheI'IllOnuclear Fusion" was held at Chateau de Bonas, Castera-Verduzan, Gel's, France, from 13th to 24th August 1979, and this volume contains the text of the invited lectures. The Institute was supported by the Scientific Affairs Division of NATO, and additional support was received from EURATOM and the United States National Science Foundation. The Institute was attended by 88 scientists, all of whom were active research workers in control of thermonuclear plasmas, 01' atomic and molecular physics, 01' both. In addition to the formal lectures, printed in this volume, which were intended to be pedagogic, more than twenty research seminars were given by participants. The first half of the Institute was directed to introducing atomic and molecular theoretical and experimental physicists to the physics of controlled thermonuclear fusion. Most attention was paid to magnetic confinement, and within that field, to tokamaks. MI'.

The collision of electrons with molecules and molecular ions is a fundamental pro cess in atomic and molecular physics and in chemistry. At high incident electron en ergies, electron-molecule collisions are used to deduce molecular geometries, oscillator strengths for optically allowed transitions, and in the case of electron-impact ionization, to probe the momentum distribution of the molecule itself. When the incident electron energy is comparable to or below those of the molecular valence electrons, the physics involved is particularly rich. Correlation and exchange effects necessary to describe such collision processes bear a close resemblance to similar efft: cts in the theory of electronic structure in molecules. Compound state formations, in the form of resonances and vir tual states, manifest themselves in experimental observables which provide details of the electron-molecule interactions. Ro-vibrational excitations by low-energy electron collisions exemplify energy transfer between the electronic and nuclear motion. The role of nonadiabatic interaction is raised here. When the final vibrational state is in the continuum, molecular dissociation occurs. Dissociative recombination and dissociative attachment are examples of such fragmentation processes. In addition to its fundamental nature, the study of electron-molecule collisions is also motivated by its relation to other fields of study and by its technological appli cations. The study of planetary atmospheres and the interstellar medium necessarily involve collision processes of electrons with molecules and molecular ions."

This volume presents the contributions delivered at the "Josef-Loschmidt-Sympo sium," which took place in Vienna, June 25-27, 1995. The symposium was arranged to honor Josef Loschmidt one hundred years after his death (8 July 1895), to evaluate the sig nificance of his contributions to chemistry and physics from a modem point of view and to trace the development of scientific fields in which he had done pioneering work. Loschmidt is widely known for the first calculation of the size of molecules (1865/66), which also led to values for the number of molecules in unit gas volume and for the mass of molecules. With critical analyses of problems in statistical physics he made important contributions to the development of that field, "Loschmidt's paradoxon" continuing to be a point of departure for present day studies and discussions. For decades there was little awareness that Loschmidt was a pioneer in organic struc tural chemistry. Only in recent years has Loschmidt's first scientific publication "Chemis che Studien I", published in 1861, become more widely known and it is now recognized that with his ideas on the structure of organic molecules he was greatly ahead of the chemists of that time. The papers in these proceedings are arranged in three sections: l. Organic structural chemistry (Chapters 1-12). 2. Physics and physical chemistry (Chapters 13-26). 3. Loschmidt's biography, Loschmidt's world (Chapters 27-33).