DIELECTRIC RELAXATION AND STRUCTURE.

The measurements of dielectric constant and loss for eight rigid molecules at 2.2 mm wavelength at various temperatures were used to obtain the optical dielectric constant, the value of which was close to the square of the refractive index. There seemed to be no evidence of an additional ultrahigh frequency dispersion region. The dielectric constants and losses of ten primary alkyl alcohols at various temperatures and 16 wavelengths were used to characterize different mechanisms of dielectric relaxation in these compounds. It is concluded that the first relaxation time is determined by the rupture of hydrogen bonds in the molecular aggregates and subsequent rotation of the molecular dipoles. The second and third relaxation times are probably due to the overall rotation of the monomeric molecules present and the intramolecular rotation of the OH group, respectively. Dielectric measurements on seven waterdioxane mixtures at various temperatures and wavelengths were analyzed in terms of two separate relaxation times. The shorter relaxation time was attributed to the overall molecular rotation of free water molecules, and the longer to the partial breaking of the hydrogen bond and subsequent rotation of the dipole. Dielectric constants and losses of binary mixtures of benzophenone in tetrahydrofuran, pyridine and chloroform, 2-chloronapthalene in pyridine, and 4-iodobiphenyl in chloroform were measured at wavelengths of 2.2 mm, 1.2, 3, and 10 cm. The data gave two relaxation times, one corresponding to the larger and the other to the smaller molecule.