Depolarization density-dependent

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. 

R. A. Huijts, J. C. F. Michielsen, and J. van der Elsken. Anomalous density dependence in depolarized light scattering by simple fluids. Phys. Lett. A, 772 230-233 (1985). 

J. van der Elsken and R. A. Huijts. Density dependence of the depolarized light scattering spectrum of xenon. J. Chem. Phys., 53 3007-3015 (1988). 

H. Versmold and U. Zimmermann. Density dependence of interaction-induced scattering Contributions to the depolarized Rayleigh band of ethane. J. Chem. Soc. Faraday Trans. 2, 53 1815-1824 (1987). 

The present experiments are mute as to the timescale on which delocalization may occur. EPR results on Ru(bpy)"5 demonstrate localization of the bpy electron density in this Ru(II)(bpy)2 (bpy )+ species on the EPR timescale, but suggest that delocalization may occur on a timescale only slightly longer. It is possible that either time-resolved EPR or temperature dependent fluorescence depolarization experiments may establish the time-scale of localization in Ru(bpy) +. 

The polymerization of anions is a special type of irreversible anodic processes. Of these the oxidation of sulphate to persulphate ions has been studied in the deepest detail. In the production of pcrsulphuric acid the yield is increased to a certain limit by a higher concentration of the initial sulphuric acid and an increased current density at the anode of smooth platinum. In too concentrated sulphuric acid the pcrsulphuric acid is already hydrolysed to a considerable extent to monopersulphuric acid (Caro s acid), which then acts as a depolarizer and lowers the required high potential at the anode. Electrolysis of sulphate solutions also gives persulphates and in this reaction the current efficiency will depend on the nature of the cation the efficiency increasing in the order of Na+, K+ and NHj. 

H. Versmold and U. Zimmermann. Depolarized Rayleigh scattering Temperature dependence of molecular reorientation of COj at constant density. Molec. Phys., 50 65-75 (1983). 

In this book we have often asserted that because atoms are optically isotropic, there should be no depolarized light scattering that is, Ivh = 0. Nevertheless, it has been demonstrated recently (see the pioneering work of McTague and Birnbaum, 1968 and the review by Fleury and Boon, 1974) that there is a substantial depolarized component from atomic fluids. The observed depolarized spectrum from monatomic fluids has an exponential frequency-dependence. Fleury et al. (1971) have studied Ivh( >) over a wide range of densities and temperatures and have found that Ivh(co) can be fitted to a two-branch exponential spectrum... 

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