It is undoubtedly true that much of the progress in the quant~m theory of matter is due to the remarkable success of the independent particle model (IPM)--especially in describing ground states. However, the accurate experimental results of the last 10 years or so, on a variety of spectroscopic phenomena and chemical processes which involve the Excited State, and the related failure of the IPM to reproduce accurately--in many cases, even qualitatively--the observed data, have sent to theorists a clear message: There is need to create and/or apply general and useful approaches to the many-electron problem of the excited state which go beyond the IPM, treat electron correlation and relativity and explain or predict all relevant physical or chemical information with consistent accuracy. This book contains articles devoted mainly to some of the most important new developments in Quantum Chemistry concerning the theoretical foundations and the computational implementation of many-body approaches to the quantitative and detailed under standing of the electronic excited states of atoms, molecules and solids. Furthermore, it contains experimental and pheno menological articles on Photoelectron and Auger spectroscopy, Lifetime measurements and Organic Photochemistry. In combination or individually, these articles constitute a good description of some current theoretical and experimental work on the electronic structure and spectroscopy of atoms, molecules, polymers, surfaces, metal oxides and amorphous solids.

Methods of scientific investigation can be divided into two categories: they are either macroscopic or microscopic in nature. The former are generally older, classical methods where the sample as a whole is studied and various local prop erties are deduced by differentiation. The microscopic methods, on the other hand, have been discovered and developed more recently, and they operate for the most part on an atomistic scale. Glancing through the shelves of books on the various scientific fields, and, in particular, on the field of physical metallurgy, we are surprised at how lit tle consideration has been given to the microscopic methods. How these tools provide new insight and information is a question which so far has not at tracted much attention. Similar observations can be made at scientific confer ences, where the presentation of papers involving microscopic methods is often pushed into a far corner. This has led users of such methods to organize their own special conferences. The aim of this book is to bridge the present gap and encourage more interaction between the various fields of study and selected microscopic meth ods, with special emphasis on their suitability for investigating metals. In each case the principles of the method are reviewed, the advantages and successes pointed out, but also the shortcomings and limitations indicated.

The Theory and Practice of Scintillation Counting is a comprehensive account of the theory and practice of scintillation counting. This text covers the study of the scintillation process, which is concerned with the interactions of radiation and matter; the design of the scintillation counter; and the wide range of applications of scintillation counters in pure and applied science. The book is easy to read despite the complex nature of the subject it attempts to discuss. It is organized such that the first five chapters illustrate the fundamental concepts of scintillation counting. Chapters 6 to 10 detail the properties and applications of organic scintillators, while the next four chapters discuss inorganic scintillators. The last two chapters provide a review of some outstanding problems and a postscript. Nuclear physicists, radiation technologists, and postgraduate students of nuclear physics will find the book a good reference material.