Light Scattering from Optically Active Fluids

Abstract

A rigorous theory for the light scattered from a solution of an optically active species is presented. The theory is based on the quantum‐mechanical time displaced correlation function for the suceptibility tensors. This formalism leads to the correct form of the Kronig–Kramers relations. Otherwise, the procedure follows the usual theory of light scattered from inactive solutions. The result shows that the parameters usually associated with the optical rotatory power and the ellipticity are linear combinations of two rotational invariants of the fourth‐rank tensor formed by the direct product of the dielectricpolarizabilitytensor and the pseudotensor that gives the optical activity. Only for isotropic molecules do we recover the classical result. The depolarization of the light (or ellipticity) is due both to the dielectricpolarizability and to the optical activity pseudotensor. If the scattering experiment is done at an angle different from zero, then information about the anisotropy of the molecular susceptibility tensor be obtained. Also, when the system is opalescent, it could be more convenient to look at the scattered light instead of the “transmitted” one.