Electric Polarization of Onsager Fluids. II. Birefringence. 1. Kerr Constants of Pure Substances

Abstract

The Kerr constants of pure liquid organic compounds, which exhibit weak intermolecular interactions and possess widely varying electric, optical and polarizational molecular parameters, were computed from the data on dielectrometry and electric birefringence. Good agreement of the calculated and observed values was reached as the result of the introduction of the local field model, which develops the concepts of reactive field and local electric induction of a polarized fluid, into the orientational theory of the Kerr effect.

Electric Polarization of Onsager Fluids. II. Birefringence. 3. Role of Universal Pairwise Interactions

“…Further refinement of the theory of EB by explicitly considering high and low frequency molecular polarizabilities, substituting Onsager cavity for a sphere, filled with a solute "medium" and a point dipole in the center, and introducing an oscillating local electric induction function [2], leads to an improved description of electrostatic energy (5) of solute-solvent interaction. This, in turn, enabled us to carefully examine basic ideas of the theory of EB of condensed media and make its predictions more accurate [3]. Our studies on dielectric and electrooptical properties of dilute binary solutions presented here unambiguously evidence in favor of these modifications of the theory: ΔmKg2l 1 > ΔmKg22 > ΔmKg23 and tgφ1 > tgφ2 > tg 3 for all values of stuctural and physical-chemical properties of solutes, solvents, and solutions.…”

“…This unphysical situation cannot correspond to the gaseous phase of solutes. Relative errors in the extrapolated values of (mΚg2l)e determined according to [19] (l = 1), [20] (l = 2), and [3] (l = 3) with respect to the corresponding experimental gaseous , phase values mK? form a series of inequalities ΔmKg2 > ΔmKe2 > ΔmKe3.…”

“…Staying within the limits of this approach we introduced a new internal field model [2] developing the concepts of reactive field and local electric induction. Later, with the help of the model we developed a theory of EB of molecular condensates [3]. In particular, we derived where Kg is an observed birefringence of molecules with dynamic polarizability α; M, n, and p are molecular weight, refraction index and density of the medium; g and t are cavity and reactive internal field faction [4].…”

“…and the corresponding gas phase values is the main test of the theory. The basic idea of our approach to systematically account for reactive field contribution to the total potential energy of a medium held under EB conditions by substituting Lorentz field by Onsager field or its modiflcations has been checked against experimental and theoretical data on organic compounds characterized by a wide range of polarizational and stuctural properties [3,16].…”

Electric Polarization of Onsager Fluids. II. Birefringence. 2. Molar Kerr Constants of Binary Solutions

“…From the experimental data on dielectrometry and electric birefringence (EB) original expression for the computation of Kerr constants of pure molecular fluids was deduced in the previous publication [1] (K l is Kerr constant of a unit volume containing N molecules):…”