Théorie de l'anisotropie optique des mélanges de molécules différentes avec interactions

Coherent light scattering by interacting anisotropic molecules with variable dipolar polarizability

“…This, however, may lack justification when applying the G-model since, here, the crossterm contributions Ag A 1 + A1* Ao ) can be nonzero [6,9,[11][12][13][14]. These cross-contributions vanish always for the molecular S-model, the only non-zero one being the purely fluctuational contribution I A 1 I2 ) [6,8,11] ] usually taken into account in the spectral theories [15][16][17][18][19][20]. But it should be kept in mind that contributions of the same order as I A 12 > give non-zero cross-terms [7,8,11,13] ( Aa A2 + Ai Ao ) in the S-model.…”

“…The depolarization of light due to changes in polarizability of anisotropic molecules in condensed gas mixtures has also been analysed [8,9], applying two (*) This research was supported by the Polish Academy of Sciences (Research Project MR 1.9). distinct molecular models : (i) the S-model (specific model), considering the anisotropic molecules as correlated radially but having statistically independent orientations [4,5,7,8], and (ii) the (general) G-model, considering both the positions and orientations of the anisotropic molecules as statistically dependent [9][10][11][12][13].…”

“…In their theoretical description of the spectral distribution of light scattered by anisotropic molecules, some authors [15][16][17][18][19][20][21][22] [6][7][8][9] and, in particular, recent papers [14][15][16][17][18] are restricted to calculations of the first order perturbations A 1. This, however, may lack justification when applying the G-model since, here, the crossterm contributions Ag A 1 + A1* Ao ) can be nonzero [6,9,[11][12][13][14].…”

“…These cross-contributions vanish always for the molecular S-model, the only non-zero one being the purely fluctuational contribution I A 1 I2 ) [6,8,11] ] usually taken into account in the spectral theories [15][16][17][18][19][20]. But it should be kept in mind that contributions of the same order as I A 12 > give non-zero cross-terms [7,8,11,13] ( Aa A2 + Ai Ao ) in the S-model. It is noteworthy that, in the molecular S-model, the factor causing the Lorentz-Lorenz function to be density-dependent is precisely the second-order change in molecular polarizability A 2 ) [4,5], whereas the first-approximation variation A 1 ) gives non-zero contributions but in the G-model [5, 23, Above, a(i)t] is the linear polarizability tensor of the i-th isolated molecule.…”

“…distinct molecular models : (i) the S-model (specific model), considering the anisotropic molecules as correlated radially but having statistically independent orientations [4,5,7,8], and (ii) the (general) G-model, considering both the positions and orientations of the anisotropic molecules as statistically dependent [9][10][11][12][13]. On the latter G-model, analytical and numerical calculations have been successfully carried out to the end for the radial-angular correlations with regard to the two limiting cases of (i) weak angular (tensorial) interactions, dealt with as a perturbation to the radial interactions [6,8,11 ], and (ii) strong angular interactions, expressed in terms of two-parameter Langevin functions [12][13][14].…”