Étude théorique et expérimentale de la dépolarisation du rayonnement Rayleigh diffusé par les gaz rares comprimés

Abstract

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Molecular Motions in CCl4: Light Scattering and Infrared Absorption

“…This effect has been postulated to be the main contribution to the depolarized scattering from noble gases. 9 In the limit of high densities such as those found in a liquid, this effect should be severely suppressed relative to that expected on the basis of the intensity observed in the gas. However, there may still be sufficient fluctuations in the local field owing to fluctuations in local order in the liquid to contribute an observable amount of intensity to the scattering.…”

A comparative study of Rayleigh and Raman depolarized light scattering by a pure fluid of isotropic molecules

“…In contrast with the much investigated depolarized Rayleigh scattering [1][2][3], previous studies of the depolarized Raman scattering were generally limited to low density gases [4]. For (2), (8), one obtains for the Rayleigh and Raman VV scattering :…”

“…Then (9) gives since the contributions of the four terms Q Qm, Q i Q n@ Q j Q m, Q i Q" are equal (1 [2] and Alder [8], it is convenient to classify the various terms in (20) in doublets (two equivalent possibilities : Sfj3 Sfj3 and S(% S{i3)' triplets (four equivalent possibilities : S'j Sf'3(j =1= n), S 13 ij S'rJ(i =1= m), S% SQ §( j # m), Sfj3 S/)(I # n)), and quadruplets (Sfj3 S'r3, where all indices are different). The factor A(p) disappears when passing to the depolarizing ratio :…”

“…The high density limit (p/po 1). -The only complete treatment of this limit is based on the lattice model (or vacancy model) of Thibeau et al [1], [3].…”

Optical properties and molecular interactions

“…The results of Thibeau 3 showed three regions for the ratio i/1 (Figure 1): the first corresponding to binary collisions, and then a slower increase, corresponding to a much slower increase of i, since I decreases strongly, the medium approaching liquid densities.…”