Dynamics of Disordered Materials

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.

Autorentext
Dieter Richter, geboren 1938 in Hof, war bis 2004 Professor für Kritische Literaturgeschichte an der Universität Bremen und ist Autor zahlreicher, in Deutschland und Italien erschienener Bücher zur europäischen Kulturgeschichte. Er lebt in Bremen und ist Ehrenbürger von Amalfi. Für sein Buch »Der Süden. Geschichte einer Himmelsrichtung« erhielt er den NDR Kultur Sachbuchpreis 2009.

Inhalt
I Introduction to Neutron Scattering.- Inelastic Scattering of Neutrons as a Tool to Study the Glassy State.- II Dynamics Around the Glass Transition.- Neutron Scattering Anomalies Near the Glass Transition Singularity.- Polymer Dynamics Near the Glass Transition.- Dielectric Relaxation Behaviour Around the Glass-Transition of Polar Polymeric Systems.- Primary Glass Tranisition in a Molecular Glass as Observed by Incoherent Neutron Scattering.- A Contribution of Neutron Scattering to a New Understanding of the Glass Transition.- ?-NMR on LiCl 7D20 in the Glassy and the Liquid State.- Dynamics of Two-Component Systems Near the Glass Transition.- Relaxation of the Incoherent Density-Density Correlation Functions of Binary Soft-Sphere Glasses and Jump Motion of Atoms Near the Glass Transition.- Yukawa Systems: Model for Colloidal Glasses.- Non-exponential Decay of Density Correlation Function in Dense Microemulsions.- Free-Volume Distribution in Organic Glasses Studied by 2H NMR of Deuterated Probes.- Scaling Properties of Fast Motions in a Globular Protein.- The Structural and Dynamical Properties of the Sol-Gel Transition.- Ordinary and Supercooled States in a Liquid Rubidium Model.- Dynamics of o-Terphenyl in Its Glassy and Supercooled Liquid State as Observed by Incoherent Neutron Scattering.- Dielectric Relaxation in Microemulsions Near the Percolation Threshold.- Structure and Dynamics of Cyclohexane in Bulk and Constrained Geometry.- Dynamic Properties of an Inorganic System Near the Glass Transition.- A Stochastic Model for Phase Transitions.- Kawasaki Dynamics in the Ising Chain.- Signatures of Critical Dynamic Instability Near the Glass Transition: A Neutron Scattering Study.- III Low Frequency Excitations.- Low Frequency Excitations in Glasses.- StructuralRelaxation in a Metallic Glass.- Low-Energy Excitations and Vibrational Modes in Amorphous Zr-Cu Alloys.- Low Frequency Excitations in Al-Ge Alloys Quenched Under High Pressure.- Opposite Extreme Structural Relaxation Behaviour in Glassformers; a Brillouin Scattering Study of B2O3 and Ca0.4K0.6(NO3)1.4.- Line Shape Analysis of Brillouin Spectra from Glassforming Liquids.- Acoustic Glass Relaxations and Mesomorphic Transitions in Polymer Liquid Crystals.- Very Low Frequency Light Scattering in Amorphous Silica.- Longitudinal and Transverse Brillouin Intensities in Glasses: Experiments and Interaction Induced Contributions.- Phonons in Glasses.- Vibrational States and Tunneling.- IV Spin Glasses and Orientational Glasses.- Critical Dynamics of the Spin Glass Transition.- Random Fields and Nonergodicity in the Orientational Glass K(CN) x Br1?x.- Nature of the Glass Transition in (NaCN)1?x (KCN) x.- Correlation Between Glass Behaviour and an Intrinsic Limit of Metastability: A Time Resolved Investigation.- The Effect of Orientational and Composition Disorder on the Low Temperature/Low Energy Rotational Excitations of the NH3 Groups in Calciumhexaamine Ca(NH3)6.- What Stabilizes the Orientational Glass Phase?.- Neutron Scattering Study of a Crystal with Random Competing Interactions.- Quasielastic Broadening of the Coherent Diffuse Scattering from the Orientational Glass (KBr)l?x(KCN)x.- V Fractal Dynamics.- Dynamics of Tenuous Structures.- Dynamics of Silica Networks.- Crossover in the Vibrational Density of States of Silica Aerogels.- Low Frequency Vibrations in Silica Aerogels.- Low Frequency Light Scattering in Lithium Borate Glasses; a Cross-Over from Phonons to Fractons?.- Index of Contributors.