This volume contains the lecture notes of ten courses given at the XIV Latin American School of Physics (XIV LASP) which took place in Caracas, Venezuela, from the 10th to the 28th of July 1972. The LASP is held each year in a different Latin American country. Its purpose is to bring together young Latin American physicists at the doctorate level to attend lectures given by well known scientists. The participants are also invited to give seminars on their research work. The topics of the courses given this year were chosen according to the existent fields of interest in Latin America. Two of these courses, namely those covering astrophysics and biophysics were given in such a way as to be accessible to all par ticipants independently of their main field of interest. The XIV LASP has received financial support from institutions in Venezuela and abroad, making possible a meeting of ninety-two Latin American physicists and ten distinguished lecturers. For this we are indebted to the following Institutions: Consejo Nacional de Investigaciones Cientificas y Tecnologicas de Venezuela, Organization of American States, Instituto Venezolano de Investigaciones Cientificas, and its physicists, Universidad Central de Venezuela, Consejo de Desarrollo Cientifico y Humanistico de la U.C.V., Universidad Simon Bolivar, Embassy of U.S.A. in Venezuela, Embassy of France in Venezuela, The British Council in Venezuela, Ministerio de Educacion de Venezuela and the Latin-American Center of Physics.

Computation is essential to our modern understanding of nuclear systems. Although simple analytical models might guide our intuition, the complex ity of the nuclear many-body problem and the ever-increasing precision of experimental results require large-scale numerical studies for a quantitative understanding. Despite their importance, many nuclear physics computations remain something of a black art. A practicing nuclear physicist might be familiar with one or another type of computation, but there is no way to systemati cally acquire broad experience. Although computational methods and results are often presented in the literature, it is often difficult to obtain the working codes. More often than not, particular numerical expertise resides in one or a few individuals, who must be contacted informally to generate results; this option becomes unavailable when these individuals leave the field. And while the teaching of modern nuclear physics can benefit enormously from realistic computer simulations, there has been no source for much of the important material. The present volume, the second of two, is an experiment aimed at address ing some of these problems. We have asked recognized experts in various aspects of computational nuclear physics to codify their expertise in indi vidual chapters. Each chapter takes the form of a brief description of the relevant physics (with appropriate references to the literature), followed by a discussion of the numerical methods used and their embodiment in a FOR TRAN code. The chapters also contain sample input and test runs, as well as suggestions for further exploration.

This book is written for graduate students just beginning research, for theorists curious about what experimentalists actually can and do measure, and for experimentalists bewildered by theory. It is a guide for potential users of spectroscopic data, and uses language and concepts that bridge the frequency-and time-domain spectroscopic communities. Key topics, concepts, and techniques include: the assignment of simple spectra, basic experimental techniques, definition of Born-Oppenheimer and angular momentum basis sets and the associated spectroscopic energy level patterns (Hund's cases), construction of effective Hamiltonian matrices to represent both spectra and dynamics, terms neglected in the Born-Oppenheimer approximation (situations intermediate between Hund's cases, spectroscopic perturbations), nonlinear least squares fitting, calculation and interpretation of coupling terms, semi-classical (WKB) approximation, transition intensities and interference effects, direct photofragmentation (dissociation and ionization) and indirect photofragmentation (predissociation and autoionization) processes, visualization of intramolecular dynamics, quantum beats and wavepackets, treatment of decaying quasi-eigenstates using a complex Heff model, and concluding with some examples of polyatomic molecule dynamics. Students will discover that there is a fascinating world of cause-and-effect localized dynamics concealed beyond the reduction of spectra to archival molecular constants and the exact ab initio computation of molecular properties. Professional spectroscopists, kinetics, ab initio theorists will appreciate the practical, simplified-model, and rigorous theoretical approaches discussed in this book. - A fundamental reference for all spectra of small, gas-phase molecules - It is the most up-to-date and comprehensive book on the electronic spectroscopy and dynamics of diatomic molecules - The authors pioneered the development of many of the experimental methods, concepts, models, and computational schemes described in this book

Theoretical and experimental work on solids with low-dimensi℗Ư onal cooperative phenomena has been rather explosively expanded in the last few years, and it seems to be quite fashionable to con℗Ư tribute to this field, especially to the problem of one-dimensional metals. On the whole, one could divide the huge amount of recent investigations into two parts although there is much overlap bet℗Ư ween these regimes, namely investigations on magnetic exchange interactions constrained to mainly one or two dimensions and, secondly, work done on Id metallic solids or linear chain compounds with Id delocalized electrons. There is, of course, overlap from one extreme case to the other with these solids and in some rare cases both phenomena are studied on one and the same crystal. In fact, however, most of the scientific groups in this area could be associated roughly with one of these categories and, in addition, a separation between theoreticians and experimentalists in each of these groups leads to a further splitting of interests although many theories about these solids have been tested by experimenta℗Ư lists. Nevertheless, more cooperation and understanding between scientists working on low-dimensional cooperative phenomena should appreciably stimulate further development. With a better inderdis℗Ư ciplinary understanding, new ideas could possibly help chemists in synthesizing tailor-cut solids. This would in return give experi℗Ư mentalists new phenomena to examine and finally would stimulate new theoretical work.

As 1 review these pages, the last of them written in Summer 1978, some retrospec tive thoughts come to mind which put the whole business into better perspective for me and might aid the prospective reader in choosing how to approach this volume. The most conspicuous thought in my mind at present is the diversity of wholly independent explorations that came upon phase singularities, in one guise or another, during the past decade. My efforts to gather the published literature during the last phases of actually writing a whole book about them were almost equally divided between libraries of Biology, Chemistry, Engineering, Mathematics, Medicine, and Physics. A lot of what 1 call "gathering " was done somewhat in anticipation in the form of cönjecture, query, and prediction based on analogy between developments in different fields. The consequence throughout 1979 was that our long-suffering publisher re peatedly had to replace such material by citation of unexpected flurries of papers giving substantive demonstration. 1 trust that the authors of these many excellent reports, and especially of those I only found too late, will forgive the brevity of allusion I feIt compelled to observe in these substitutions. A residue of loose ends is largely collected in the index under "QUERIES. " It is c1ear to me already that the materials I began to gather several years ago represented only the first flickering of what turns out to be a substantial conflagration.

The Novartis Foundation Series is a popular collection of the proceedings from Novartis Foundation Symposia, in which groups of leading scientists from a range of topics across biology, chemistry and medicine assembled to present papers and discuss results. The Novartis Foundation, originally known as the Ciba Foundation, is well known to scientists and clinicians around the world.