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.

An attempt was made to modify the model Onsager theory. A polarizable molecular dipole enclosed in a spherical cavity is substituted for a rigid one submerged in the polarizable medium which fills the cavity. The local dielectric permittivity of the Heaviside type is replaced for the oscillating, rapidly damping function of the Fresnel integral. The analytical expressions deduced allow to estimate dipoles of free molecules, starting from the results of dielectrometry of polar fluids. The obtained values are as close as possible to the experimental data on a great variety of pure organic liquids.

On the ground of dielectrometry and electric birefringence data we calculated mołar Kerr constants of substances dissolved in organic media of diverse polarity and polarizability under t 1e conditions of infinite dilution. M i n i m a l e r r o r s o [t h e c a l c u l a t e d c o n s t a n t s , i n r e l a t i o n t o t h e i r g a s e o u s p h a s e vahes, were achieved as a result of tłe introduction of the local fiełd model, which evolves the concepts of reactive field and local electric induction of a polarized fłuid, into the orientational theory of Kerr effect.

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A comparative study of the methods of interpretation of solvent influences on electric properties of molecules was conducted based on experimental dielectric properties of dilute solutions of organic substances of various polarity. It was shown that the solvent effect estimated via London-Debye-Keesom pairwise interaction potentials is best accounted for by theories of polarization of condense media which develop the anzatzes of reactive field and local dielectric permittivity.