Dielectric loss, viscosity and intermolecular forces in liquids

Further measurements of dielectric constant and loss, in the microwave region have been carried out upon pure polar liquids and upon solutions of polar molecules in non-polar liquids of widely varying viscosities. Earlier measurements showed that the wavelength at which the loss was a maximum, that is, the critical wavelength, increased with increasing viscosity of the liquid and size of the molecule, usually, conforming poorly to the requirements of the Debye theory. New measurements show that spherical polar molecules orient in an alternating electric field with only slight dependence upon the viscosity of the medium, while unsymmetrical molecules which displace their neighbors in the process of orientation are much more dependent upon the viscosity of the liquid. Dipole-dipole forces between molecules displace the region of maximum loss to longer wavelengths, that is, lower frequencies.