Dielectric relaxation theoretical interpretation

The structural interpretation of dielectric relaxation is a difficult problem in statistical thermodynamics. It can for many materials be approached by considering dipoles of molecular size whose orientation or magnitude fluctuates spontaneously, in thermal motion. The dielectric constant of the material as a whole is arrived at by way of these fluctuations but the theory is very difficult because of the electrostatic interaction between dipoles. In some ionic crystals the analysis in terms of dipoles is less fruitful than an analysis in terms of thermal vibrations. This also is a theoretically difficult task forming part of lattice dynamics. In still other materials relaxation is due to electrical conduction over paths of limited length. Here dielectric relaxation borders on semiconductor physics. 

The DRIS formalism has been recently used [84] for the theoretical interpretation of dielectric relaxation measurements of bulk cis-polyisoprene (cis-PIP)... 

The theoretical basis of MW dielectric heating has been thoroughly reviewed elsewhere/ " and therefore only a brief summary of the important points is presented in this chapter. The important parameter in deciding the extent of interaction between MW radiation and a particular solvent is the average rotational frequency, or its inverse, the average relaxation time. Debye first proposed that this relaxation time depended on the size of the molecule and the nature of the intermolecular forces. In the Debye interpretation, for a spherical molecule with a radius r rotating in a viscous continuum, the relaxation time, t, is defined as... 

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