Depolarization of light

The depolarization of light scattered at 90° by PP and PS is treated according to RIS theory. Numerical calculations are carried out as functions of the statistical weight parameter to governing interactions of second order, of the locations of the rotational states, of the chain length expressed by the number x of repeat units, and of the stereochemical composition expressed by the fraction of racemic diads. 

The depolarization of light by dense systems of spherical atoms or molecules has been known as an experimental fact for a long time. It is, however, discordant with Smoluchowski s and Einstein s celebrated theories of light scattering which were formulated in the early years of this century. These theories consider the effects of fluctuation of density and other thermodynamic variables [371, 144]. 

P. Thoman, K. Burnett, and J. Cooper. Observation of dynamic correlations in collisional redistribution and depolarization of light. Phys. Rev. Lett., 45 1325, 1980. 

Here, an and a are the polarizabilities of the diatomic complex parallel and perpendicular to the internuclear separation, R12. A purely classical theory, which accounts for the electrostatic distortion of the local field by the proximity of a point dipole (the polarized collisional partner), suggests that )S(Ri2) 6ao/Ri2 with (Xq designating the permanent polarizability of an unperturbed atom. This expression is known to approximate the induced anisotropy of such diatoms fairly well. This anisotropy gives rise to the much studied pressure-induced depolarization of scattered light and to depolarized CILS spectra in general. The depolarization of light by dense systems of spherical atoms or molecules has been known as an experimental fact for a long time. It is, however, discordant with Smoluchowski s and Einstein s... 

For some time, it was known [159,160,390,405] that the depolarization of fluids composed of isotropic atoms or molecules is nonvanishing if the particle density is sufficiently high. The density-dependent depolarization of light by isotropic fluids is now understood to be caused by the anisotropy of the collision-induced polarizability increment of two or more interacting atoms or molecules [177, 178,376, 390]. Depolarization ratios are often expressed in terms of a virial series whose nth term accounts for the n-body interactions, with n = 2, 3. . . [161, 164, 165, 167, 170, 175]. Fluids composed of optically anisotropic molecules show a variation of the depolarization ratio with density that is understood as arising from the interplay of the permanent and induced anisotropies the anisotropy of the interaction potential also plays a role [161, 188]. The literature concerned with density-dependent depolarization of light is included in Section 1.2. By contrast, CILS spectroscopy is considered in Section 1.3. 

W. M. Gelbart. Many-body effects and the depolarization of light by simple gases. J. Chem. Phys., 57 699-701 (1972). 

F. J. Pinski and C. E. Campbell. Depolarization of light and pair-pair correlations of argon gas. Chem. Phys. Lett., 56 156-160 (1978). 

S. Kielich. Depolarization of light scattering by atomic and molecular solutions with strongly anisotropic translational-orientational fluctuations. Chem. Phys. Lett., 70 516-521 (1971) Erratum, 79 609 (1973). 

B. Depolarization of Light in Rayleigh, Hyper-Rayleigh, and Pure... 

The systems containing dispersed particles with anisotropic polarizability possess some unique optical properties. The axis of dipole induced by primary wave in such a particle does not coincide with the direction of electric vector in incident light wave. As a result, upon irradiation with polarized light, the dipole moments of chaotically distributed particles form different angles with respect to the initial direction of polarization. This leads to the appearance of perpendicularly polarized components in the scattered wave, i.e., partial depolarization of light occurs (Fig. V-26) [21]. 

The depolarization of light by atomic gases 462 and the use of Raman scattering to probe exciton-phonon coupling in molecular crystals 463 have been discussed. 

Doty, P. Depolarization of Light Scattered from Dilute Macromolecular Solutions. I. Theoretical Discussion. J. Polymer Sci. 3, 750—762 (1948). 

In some cases, other second-hyperpolarizability quantities may be required, such as for the Kerr effect, which measures the depolarization of light in the presence of a DC field. The corresponding second hyperpolarizability is given as... 

R.L. Rowell, G.M. Aval, J.J. Barrett, Rayleigh-Raman depolarization of light scattered by gases. J. Chem. Phys. 54(5), 1960-1964 (1971)... 

In the bulk there is a twisted structure with the helix axis being parallel to the plates, near the plates there is perpendicular alignment. In this state the texture is focalconic — the helix axis deviating more or less strongly from a direction parallel to the plates — causing diffuse scattering and depolarization of light. 

The rotational mobility of molecules in the excited state will induce the depolarization of light, causing excitation polarized light and fluorescence emission to have different angular displacements. 

Benoit H. Depolarization of light scattered by chainlike molecules. Comptes Rendus 1953 236 687-689. 

N. Kirov, P. Simova, M. Sabeva, Depolarization of light scattered in nematic liquid crystal. Mol. Cryst. Liq. Cryst. 1976, 33, 189. 

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