Predicted scattering patterns

Rainbow scattering has been detected from high Miller Index stepped platinum surfaces. Typical rainbow scattering patterns are shown in Fig. 4.7. The increase in intensity of the surface rainbows, as displayed by this figure, for an increase in the angle of incidence, qualitatively follows the trend predicted from calculations by McClure... 

An alternative explanation of the observed turbidity in PS/DOP solutions has recently been suggested simultaneously by Helfand and Fredrickson [92] and Onuki [93] and argues that the application of flow actually induces enhanced concentration fluctuations, as derived in section 7.1.7. This approach leads to an explicit prediction of the structure factor, once the constitutive equation for the liquid is selected. Complex, butterfly-shaped scattering patterns are predicted, with the wings of the butterfly oriented parallel to the principal strain axes in the flow. Since the structure factor is the Fourier transform of the autocorrelation function of concentration fluctuations, this suggests that the fluctuations grow along directions perpendicular to these axes. 

Figure 10.2 Small-angle light scattering pattern predicted using the Helfand-Fredrickson...

If the crystal structure of a polymer is known, it is possible to calculate the expected intensities of all the diffraction spots by using the known scattering powers of its various atoms. If, therefore, it is possible to predict the structure from the measured unit-cell dimensions and some assumed form for the polymer chains within the unit cell, it is possible to compare a predicted set of intensities with the observed diffraction pattern. If the structure assumed is close to the actual one, only minor adjustments will be needed in order to get a more perfect fit between the predicted and observed scattering patterns and thus to determine the structure. Otherwise a new prediction must be made. 

The above theory predicts a cylindrically symmetrical scattering pattern (independent of n). This is a consequence of the random... 

Fig. 41. Theoretically predicted Hr light scattering patterns for perfect and truncated sphendites. TheparameterG characterises the degree of truncation. ( From Stein, R. S. andPicot, C. (1970). J. Polymer Sci., A-2.8,3127.)...

Samuels has proposed a semi-empirical theory to account for the change in scattering patterns with deformation. He has substituted the definition of U given by eqn. (44) of Section 3.3.2 into the Stein-Rhodes eqns. (Ill) and (112). While this procedure is not rigorous, it leads to predicted patterns quite similar to that for the rigorous theory and which agree quite well with experiment. This is illustrated in Fig. 44 where the experimental Hy scattering patterns for deformed polypropylene samples may be compared with calculated patterns. 

Fig. 2.14 An array of full-wave dipoles without a groundplane will have transmitting and scattering patterns that took alike and scatters the same amount in front and back. However, when Zl =

What is your prediction of the scattering pattern for reactive collisions in the Ar+ + D2 system at high collision energies in CM Would forward or back scattering predominate (Ignore fragmentation.)... 

SANS provides a unique tool to explore stmctural details of polymeric systems and allows kinetic studies with a resolution of a few seconds or less. Phenomena observed in polymer blends allow molecular interactions to be assessed as well as proof of theoretical predictions of static and kinetic properties of, respectively, critical phenomena and phase transition (Sections 2.11.3.2 and 2.11.3.3). Quenched SANS allows the evolution of anisotropic scattering patterns after application of sudden strain thereby extending the effeaive time window for the observation of polymer relaxation and their hierarchy in systems with more complicated architeaures from spin echo toward macroscopic times using time-temperature scaling (Section 2.11.3.4). 

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