Light scattering multicomponent systems

Up to here, we have dealt with binary systems, such as pure solute in pure solvent, and mixtures of two pure components. In this section, we provide limited expansion to systems of multicomponents, that is, of more than two components. The field time-space correlation function, ( ( ,0) ( ,r)) = /( )g ( ,r), of scattered light from multicomponent systems may be given by... 

Vrij A. Light scattering of a concentrated multicomponent system of hard spheres in the Percus-Yevick approximation. J Chem Phys 1978 69 1742-1747. 

Hence, light scattering, in principle, can be observed in an inhomogeneous medium only. Th( causes and character of heterogeneities may be various an ensemble of particles of one phase in another phase (colloidal, dispense, heterogeneous systems), density fluctuations in gases (vapours) and liquids, concentration fluctuations in multicomponent one-phase systems (solutions). 

In standard light scattering experiments on polymer solutions, usually absolute scattering intensities are determined since this is necessary for the determination of molecular weights. Measurements of absolute intensities also provide additional information in X-ray or neutron diffraction studies on multicomponent- and multiphase-polymer systems. In the following we will give the equations to be used. 

Yeh and Keeler 244) extended the method of laser-scattering spectroscopy to probe systems undergoing rapid chemical reactions. They observed the spectral line broadening in light from a singlemode He-Ne laser scattered from multicomponent solutions, as a function of time. The experiment employed a pressure-scanned Fabry-Perrot interferometer and photon counting techniques. 

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