This book contains the proceedings of a workshop held at the Institute Laue-Langevin in Grenoble in September 1988. Review articles and contributed papers survey recent theoretical and experimental developments on disordered materials and in particular on glasses. A large part of the book concerns the recently proposed mode-coupling approach to the behaviour of a viscous liquid around its glass transition, where the relevant dynamics extend over a broad range in time scales and the application of quite different experimental techniques becomes essential. Contributions report on experiments using dielectric relaxation, NMR or light scattering techniques, and especially neutron scattering techniques. One signature of disordered materials is the occurrence of an excess vibrational density of states at low frequencies. Some situations are presented where the density of states can be understood by taking into account the peculiarities of intra- and intermolecular motions. Another approach to the dynamics of disordered materials is the fracton picture, developed to describe the excitations of fractal objects. Several contributions discuss the dynamics of such fractals, studying mainly the vibrational density of states, and some discuss the application of the fracton concept to materials without a fractal structure like glasses.

The Institut Max-von-Laue-Paul Langevin (ILL) in Grenoble regularly organ ises workshops that deal with the various applications of neutrons in physics, chemistry, biology and also in nuclear physics. The workshop" Atomic Trans port and Defects in Metals by Neutron Scattering," jointly organised by the Institut Laue-Langevin and the Institut fiir Festkorperforschung of the KFA Jiilich, was held in October 1985 in Jiilich. The study of problems in metal physics and in physical metallurgy is a traditional field of neutron scattering. The most commonly used methods are diffuse elastic, small-angle and inelastic scattering of neutrons. A number of problems can be identified where neutrons yield information that is supple mentary to that from other methods such as x-ray diffraction, synchrotron radiation or electron microscopy. In certain fields, for example spectroscopy for the investigation of atomic motions or for the investigation of magnetic properties, neutron scattering is a unique method. The facilities at the High Flux Reactor of the ILL, and also at the Jiilich and at other medium flux research reactors, have contributed numerous re sults in these fields. It was the aim of this workshop to give a survey of the present state of neutron scattering in metal physics."