Analysis of conflicting theories of dielectric relaxation

Abstract

Two different forms have been proposed for the relation between the frequency‐dependent dielectric constant of a polar substance and the autocorrelation function for the net dipole moment of a small spherical region inside the dielectric. We find that one of them is correct, while the other one describes a spherical sample embedded in a medium with a frequency‐independent dielectric constant equal to the static dielectric constant of the sample. A number of recent papers dealing with this question are analyzed. We discuss in particular the role played by fluctuations in the polarization of the surrounding medium near the surface of the embedded sphere.