On the Validity of the Lorentz—Lorenz Equation Near the Critical Point

Abstract

Corrections to the Lorentz—Lorenz equation for the refractive index of a fluid, due to long‐range density fluctuations, have been evaluated near the critical point, using Yvon's statistical‐mechanical theory of the refractive index, together with the Ornstein—Zernicke asymptotic form of the two‐particle correlation function. For argon, with experimentally reasonable values for the numerical parameters, the correction is smaller than one part in 10⁴.