Dielectric properties of dipolar solids

A quantitative theory of the dielectric properties of crystalline solids consisting of dipolar long-chain molecules is developed (one dipole per molecule). In these solids the dipoles are concentrated in dipolar planes. In the ground state the dipolar planes have a permanent polarization, but usually the polarizations of successive planes have opposite directions. The static dielectric constant rises with increasing temperature up to a critical temperature T0 and then decreases. At T0 the substance has a phase transition of the second kind. Comparison with experiments by Muller on a solid ketone lead to good agreement. For chains with an even number of C-atoms metastable states with a permanent polarization are predicted, and a method to reach these states is discussed. The interaction between dipoles plays a predominant role at temperatures below T0. It is shown that Lorentz’s or Onsager’s methods are invalid in this temperature range.