Localization effect, light scattering

The incorporation of non-Gaussian effects in the Rouse theory can only be accomplished in an approximate way. For instance, the optimized Rouse-Zimm local dynamics approach has been applied by Guenza et al. [55] for linear and star chains. They were able to obtain correlation times and results related to dynamic light scattering experiments as the dynamic structure factor and its first cumulant [88]. A similar approach has also been applied by Ganazzoli et al. [87] for viscosity calculations. They obtained the generalized ZK results for ratio g already discussed. 

When investigating the polar structure by photo-induced light scattering we assume that the largest contribution to the initial optical noise is due to diffraction of the pump beam on optical inhomogeneities located at boundaries of ferroelectric domains [9], Figure 9.12 illustrates this concept schematically. Internal electric fields Ei (random fields) yield local perturbations 5n of the index of refraction via the linear electro-optic effect 5n = - n rssEi. 

Statistical Fluctuations. Thermodynamic systems in general present unordered random deviations from equilibrium referred to as statistical fluctuations. Even slight fluctuations are apt to give rise to experimentally accessible effects. Thus, as shown by Smoludiowski, local fluctuations in density in gases and liquids cause light scattering by optically transparent media. Attempts to raise the sensitivity of measuring devices are fmled by... 

Porous photoetching of -type GaP in H2SO4/H2O/H2O2 leads to the formation of macroporous GaP (random networks of single crystalline GaP with pore sizes of 150 nm and porosity of 35 to 50% for porous etched and porous photoetched, respectively), which appears to be the most strongly scattering material in visible light reported to date and localization effects are anticipated [224, 225]. 

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