Molecular Model for Critical Opalescence of Carbon Dioxide

Abstract

Taking into consideration the fact that the variance of the density of critical CO₂ is small, a molecular model of critical CO₂ is formulated for the first time. Based on it, the intensity of Rayleigh light scattering is calculated. The expression for the Rayleigh scattering intensity differs from the Ornstein–Zernike formula by a more complex dependence on the scattering angle and on the diffraction parameter. The scattering process shows the features necessary for the critical opalescence. For the first time, the contribution of thermal motion of molecules to Rayleigh light scattering on a critical medium is explicitly reckoned.