Diffusion elastic

At higher temperatures, scattering processes other than diffuse elastic scattering are effective which account for the differences with experimental data for the contact of two solids [75-76],... 

Besides the inelastic component, always a certain number of He atoms are elastically scattered in directions lying between the coherent diffraction peaks. We will refer to this scattering as diffuse elastic scattering. This diffuse intensity is attributed to scattering from defects and impurities. Accordingly, it provides information on the degree and nature of surface disorder. It can be used for example to study the growth of thin films or to deduce information on the size, nature and orientation of surface defects Very recently from the analysis of the diffuse elastic peak width, information on the diffusive motion of surface atoms has been obtained. ... 

Equation 18.60 is valid for any object that follows a translational diffusion no matter what its actual form is. If the object is not a rigid sphere then will have other dynamical modes that contribute to the fluctuations in the scattered field, such as rotational diffusion, elastic modes, which will also contribute to the scattered intensity, as discussed later. 

Figure 2. Diffuse elastic scattering from pure water placed in the sample cell to be used for supercritical water solution measurements. Dotted curve, Bragg peaks from cell. Solid curve, the contribution from the water obtained by subtracting the cell contribution.

As implied above, the complete setup for measuring diffuse elastic x-ray scattering from supercritical solutions has been assembled. The cells and their seals have been successfully tested up to the maximum pressure. What remains for the sample containing portion of the apparatus is to test it under supercritical conditions by adding the elevated temperature. 

Fig. 5.4 Illustration of difFusive-elastic-metal model for conjugated polymers (a) Schematic of double-layer charging and diffusion (b) equivalent circuit model. Reprinted from [Fang et al. (2008d)j with permission from Elsevier, Copyright 2008.

Fig. 5.14(a)-(c) show the impedance spectra for a sample under the bias voltages of 0 V, 0.5 V, and I V, respectively. The sample had dimensions of 30 X 6 X 0.17 mm . In each figure, the measured data are compared with the predictions from both the diffusive-elastic-metal model (5.6) and the redox level-dependent model (5.25). Details on model parameter estimation can be found in [Fang et al. (2008b)]. While the two models provide comparable match with the experimental data at low redox levels (Fig. 5.14(a)),... 

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