[en] Neutron quasi-elastic scattering experiments in the smectic H, C and A phases of TBBA are presented, using the high resolution backscattering technique. The data are analyzed in terms of translational motion and are characterized by an apparent self diffusion coefficient Dsub(ap). The physical meaning of Dsub(ap) is discussed in terms of the true bulk self diffusion tensor and other kinds of translational motions

[en] The dynamics of glasses shows some distinct differences with respect to the crystalline state. Both in the short time regime (boson peak) and the microscopically slow regime (alpha- and beta-relaxation) there are glass-typical features. The outstanding sharpness of nuclear transitions offers a new tool to investigate the properties of glasses at long times, i.e., some nanoseconds to microseconds. The article will give a short introduction to glass-dynamic and convenient parameters for the theoretical description and will summarize recent results on model systems

[en] We investigate the degree to which the scaling functions f(ψ^') derived from inclusive electron-nucleus quasielastic scattering define the same function for different nuclei. In the region where the scaling variable ψ^'<0 , we find that this superscaling is experimentally realized to a high degree. copyright 1999 The American Physical Society

[en] The properties of quasi-elastic electron scattering with respect to the scaling variable y=#betta#/q-q/2M are examined. It is shown that different sets of scattering experiments can indeed be related through the scaling variable. (orig.)

No abstract available

[en] The diffusion of hydrogen in β-PdH has been studied by quasielastic neutron scattering. It is shown that the diffusion occurs through jumps between adjacent octahedral interstitial sites. The observed integrated quasielastic intensities cannot be described by a simple Debye-Waller factor. The phase transition from the β-phase to the α-phase has also been studied. No dramatic changes in the scattering patterns were observed. It is concluded that the diffusion mechanism is remarkably similar between the low concentration α-phase and the high concentration β-phase

[en] We demonstrate the maximum entropy method for the deconvolution of high-resolution tunneling data acquired with a quasi-elastic spectrometer. Given a precise characterization of the instrument resolution function, a maximum entropy analysis of lutidine data obtained with the IRIS spectrometer at ISIS results in an effective factor-of-three improvement in resolution. (orig.)

[en] A quasielastic neutron scattering experiment has been performed on a large single crystal of α-Ag₂Se. Spectra were taken at 250⁰C, under different orientations of the crystal. The spectra typically contain a narrow and a broad quasielastic component, plus some broad medium-energy-transfer inelastic scattering. The narrow component is consistent with a continuous model in which the silver ions are assumed to diffuse within a system of <100> channels. The broad component is essentially ascribed to a localized irregular movement of the silver ions. The broad inelastic contributions to the spectra reflect highly damped periodic motions of the ions. (Auth.)

[en] A critical discussion of the quasi-elastic scattering of neutrons by incoherent (hydrogenous) liquids is presented. Using the line shape expression a comparative discussion of several phenomenological models has been carried out. Extension of the Singwi-Sjoelander zero phonon expression, for the jump-diffusion model, so as to include the one phonon expression has also been given. For a delayed diffusion model a complete treatment of S(K, ω) is presented. Along the lines of the macroscopic diffusion cooling, a microscopic diffusion cooling effect in fluids is speculated

[en] Coherent diffuse scattering from single crystals of six concentrations of Y₂O₃ in ZrO₂ has been studied at temperatures between 293 K and 2780 K. The results are interpreted in terms of the scattering calculated from a model of the crystal comprising a vacancy-free tetragonal region, and a region in which there are vacancies and aggregates of vacancy pairs with a range of sizes. The vacancies and possibily the smaller aggregates appear to be most mobile as the temperature increases. 12 refs.; 3 figs