Solvent Action on Optical Rotatory Power

A general theory of the optical rotatory power of liquids is developed. The method of C. G. Darwin, supplemented so that the fundamental quantities Sαβγ...† which appear there are related to the properties of the molecules comprising the medium, is followed. The optical properties of a molecule are given by a set of tensors σ′ αβγ.... The concept of deformation leads naturally to a simple relation between the σ′ αβγ...'s and the field acting on the molecule. The electrostatic field of the dipoles of the surrounding molecules is computed for the limiting cases of imperfect gases and dilute solutions, for molecules of simple geometrical configuration. This field is identified with the solvent field. For these idealized systems, the rotatory power of a molecule in various solvents is determined in terms of quantities characteristic of the solvents. The resulting equations are controlled by comparing with the behavior of actual liquids.