Disordered materials, dynamic

Donth E (2001) The Glass Transition relaxation dynamics in liquids and disordered materials. Springer, Berlin, p 1-418... 

E. Donth, The Glass Transition Relaxation Dynamics in Liqids and Disordered Materials,... 

Dianoux AJ, Petry W, Richter D (ed) (1993) Dynamics on disordered materials II. North-... 

Recently, the PDF method was extended to describe the local dynamics of disordered materials (Dmowski W, Vakhrushev SB, Jeong I-K, Hehlen M, Trouw F, Egami T (2006) Abstracts American conference on neutron scattering, St. Charles, IL, 18-22 June 2006, unpublished). The total PDF is obtained by the powder diffraction method so that S(Q) includes both elastic and inelastic intensities. To determine the dynamics we have to use an inelastic neutron scattering spectrometer and measure the dynamic structure factor, S(Q,a>), over a large Q and co space, and Fourier-transform along Q to obtain the dynamic PDF (DPDF). While the interpretation of the DPDF is a little... 

This chapter concentrates on the results of DS study of the structure, dynamics, and macroscopic behavior of complex materials. First, we present an introduction to the basic concepts of dielectric polarization in static and time-dependent fields, before the dielectric spectroscopy technique itself is reviewed for both frequency and time domains. This part has three sections, namely, broadband dielectric spectroscopy, time-domain dielectric spectroscopy, and a section where different aspects of data treatment and fitting routines are discussed in detail. Then, some examples of dielectric responses observed in various disordered materials are presented. Finally, we will consider the experimental evidence of non-Debye dielectric responses in several complex disordered systems such as microemulsions, porous glasses, porous silicon, H-bonding liquids, aqueous solutions of polymers, and composite materials. 

The principal result of our calculation is that the Debye theory (based on the Smoluchowski equation), when extended to fractional dynamics via a onedimensional noninertial fractional Fourier-Planck equation in configuration space, can explain the Cole-Cole anomalous dielectric relaxation that appears in some complex systems and disordered materials. A further result of our calculation is that the aftereffect solution [Eq. (66)] is, with slight modifications, the moment generating function of the configuration space distribution function. Hence the mean-square angular displacement of a dipole, and so on, may be easily calculated by differentiation. We must remark, however, that the fractional Debye theory can be used only at low frequencies (got < 1) just as... 

Donth, E. (1998) The glass transition. Relaxation dynamics in liquids and disordered material. Springer, Series in Material Sei. II, vol. 48 (Springer Verlag, Berlin)... 

Increase of the doping level, N, leads to a significant increase of mobility, up to i = 10 cm V ls but also leads to a simultaneous increase of the conductivity, up to values of the order of 10" Scm l. Large ohmic currents arc therefore expected, which increase loff currents and dramatically reduce the dynamic ratio of the corresponding devices. Hence, simultaneous increase of mobility and conductivity invalidates this approach to the improvement of charge transport efficiency in conjugated polymers and disordered materials. 

Glasses and polymer electrolytes are in a certain sense not solid electrolytes but neither are they considered as liquid ones. A glass can be regarded as a supercooled liquid and solvent-free polymer electrolytes are good conductors only above their glass transition temperature (7 ), where the structural disorder is dynamic as well as static. These materials appear macroscopically as solids because of their very high viscosity. A conductivity relation of the Vogel-Tamman-Fulcher (VTF) type is usually... 

Nuclear magnetic resonance (NMR)—Unlike other structural techniques, such as powder and single-crystal x-ray and neutron diffraction, which characterize the "long-range" order, giving an average view of a structure, solid-state NMR probes the local environment of a particular nucleus and, therefore, is highly suited to study amorphous or disordered materials, such as modified LDH. An extensive review of NMR studies related to both the structure and dynamics in LDH materials was reported by Rocha [11]. Herein, we concentrate on site-specific information available from the H and Al solid-state NMR. 

D. Richter, A. J. Dianoux, W. Petry, and J. Teixeria Springer Proc. In Physics, Vol. 37 eds. Dynamics of Disordered Materials, Springer, Berlin, 1989. 

Molecular spectroscopy and lattice dynamics of oligomeric and polymeric materials have been treated thoroughly in several textbooks or articles [16-18]. We wish to point out here a few fundamental concepts which form the basis of the understanding of the spectra of disordered materials which will follow in this discussion. 

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