Depolarization of Scattering

Flory has recently summarized the experimental evidence pertaining to local correlation and their effects on chain dimensions (49). There is experimental support for local alignment from optical properties such as stress-optical coefficients in networks (both unswelled and swelled in solvents of varying asymmetry), and from the depolarization of scattered light in the undiluted state and at infinite dilution. The results for polymers however, turn out to be not greatly different from those for asymmetric small molecule liquids. The effect of... 

Here, a. and a L are the polarizabilities of the diatom parallel and perpendicular to the internuclear separation, R12. The electrostatic theory accounts for the distortions of the local field by the proximity of a point dipole (the polarized collisional partner) and suggests that the anisotropy is given by ft Rn) 6intermolecular interactions). This is the so-called dipole-induced dipole (DID) model, which approximates the induced anisotropy of such diatoms often fairly well. It gives rise to pressure-induced depolarization of scattered light, and to depolarized, collision-induced Raman spectra in general. 

Orientation polarization Depolarization of scattered light (All results negative)... 

This valency angle is no new idea in organic chemistry. The essential fact is that this angle is now obtained directly for the first time by means of vector combination of the moments. Hitherto, however, it has only been possible to carry out these calculations for a few substances. Hence the fact is of importance that (as I shall show by means of one or two examples) the depolarization of scattered light and the Kerr effect enable us to prove the existence of such angles and to calculate their value, even when free rotation, which gives rise to errors in the vectorial combination, is present. 

Interpretation of the Second Osmotic Virial Coefhcient Depolarization of Scattered Light Polydisperse Samples Turbidimetry... 

Figure 4A.1 Diagram illustrating depolarization of scattering Let us consider the scattering firom a molecule with its optic axis in the direction of the unit vector, a, and with principal polarizabilities, ai and 02 (Figure 4A.2).

According to the laws of classical optics, depolarization of scattered radiation should disappear if the molecules are completely independent of one another and are themselves spherically symmetrical. Experimentally this is not strictly true, yet it holds with a fair degree of approximation. The inert gases and highly symmetrical compounds exhibit extraordinarily small A values, which to some extent fall within the limit of experimental... 

The methods of the Kerr effect and the depolarization of scattered light have not so far been applied to the realm of high polymers, but it is conceivable that by their aid it will be possible to obtain data for relatively complex molecules on the symmetry and form of the particles and on the position of substituents. It should, of course, be emphasized that both methods are particularly sensitive to molecular interaction and they should therefore be applied as far as possible to the gaseous state or to that of dilute solution. 

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