A theory of electric polarization, electro-optical Kerr effect and electric saturation in liquids and solutions

Abstract

I recently published some papers (Piekara 1937 a , 1938) concerning the theory of dielectric polarization in polar liquids and their solutions in non-polar solvents. I have assumed the existence of two kinds of intermolecular coupling forces. The coupling forces of the first kind are due to the directional field produced by the surrounding molecules (ordered as in a crystal lattice) of potential energy — W 1 cos θ 1 ; θ 1 is the angular displacement of the dipole axis from the momentary axis of equilibrium, which can take all possible directions in space. This idea has been derived from R. H. Fowler (1935) and P. Debye (1935 a ), who developed with the help of this conception a theory of dielectric polarization. In order to obtain a satisfactory agreement with experiments on liquids, it proved, however, necessary to assume still a second kind of coupling forces. ‘Simultaneously it has been shown, that these latter play a more important role than the first ones. The coupling forces of the second kind are due not to aggregates of well-ordered molecules, but to the next molecule, which happens to be in the neighbourhood of the molecule just considered. As a matter of fact there are several such molecules in the vicinity, the action of which should be taken into account.