Inelastic neutron scattering is a well established and important technique for studying the dynamical properties of condensed matter at the atomic level. Often, as is the case of experiments designed to study motions of hydrogen atoms, or magnetic excitations, it may yield information obtainable in no other way. Our aim in assembling this book is to produce an overview of some research topics which have come to the fore recently with the development of high neutron fluxes and high performance inelastic scattering spectrometers. The topics dis cussed here are, by and large, developing rapidly and have not reached the stage at which definitive accounts are always possible. Authors have not therefore attempted to make an extensive review of their topic, and the papers quoted in the text are, in general, those which are seen as having been important in its develop ment (they date, roughly, from the 1971 IAEA conference on neutron scattering held in Grenoble). Basic phenomena are illustrated for the most part by the discussion of one, or two, typical examples. The authors hope that the book will be useful to researchers who are not yet fully aware of the diverse range of problems to which the technique can be applied, and to students beginning research work. For this reason, the first chapter by S. w.

The aim of this chapter is to show how inelastic and quasielastic neutron scattering can be used to study dynamics in a range of materials varying from simple model systems to complex systems that are close to those used in technologically important applications. After a brief overview of the theoretical and instrumental concepts, we use examples to show how different types of atomic and molecular motions can be understood using neutron scattering experiments, frequently in combination with atomistic modeling methods. We cover aspects of physics, chemistry, biology, and materials science, but with the main focus on functional materials.