Analysis of the ionic-thermal-current peaks with a distribution in the reorientation energy

Abstract

A computer program has been written to analyze ionic-thermal-current (ITC) peaks. The reorientation energy is assumed to have a distribution of width 0 around a mean value E,. The relaxation parameters E"o, r, and the number of dipoles E~are calculated by two different methods. One set is obtained after a least-squares fitting of the experimental data was performed and another set by matching a set of experimental parameters chosen with a certain criterion. The two methods are applied to analyze SrF,:I. a ITC spectra in the cases of the monoenergetic model, the I.orentzian, and the Gaussian energy distribution. The Gaussian distribution for the reorientation energy gives the most credible results, provided that the curves are eNciently cleaned. Only in this case do the two methods converge to the same set of relaxation parameters; the value of a is then an increasing function of the nominal concentration and not of X~. The origin of the curve broadening is discussed in terms of dipole-dipole interaction, and it is shown that this eAect alone is not responsible for the energy distribution. Moreover, evidence of the presence of satellite peaks on each side of the main relaxation peak is presented. These satellite peaks explain the need of analyzing only efhciently cleaned curves for obtaining reliable results.

The Molecular Interactions That Influence the Plasticizer Dependent Dissolution of Acrylic Polymer Films

“…The energy histogram was fitted to four mean distributed components, assuming a Gaussian profile for each component. The Gaussian distribution for the reorientation energy has been shown to give the most credible results, and the origin of this energy broadening has been attributed to the electrostatic interactions between dipoles and to contributions from elastic matrix deformations 21. The four Gaussian curves, labeled in the order of increasing energy ( γ 1 , γ 2 , β 1 , β 2 ), are shown in Figure 5B.…”

Dielectric characterization of the water-matrix interaction in porous materials by thermal depolarization spectroscopy

“…Q is identical to the area under the I(t) peak, and is readily obtained through graphical integration of the thermogram. If the activation energy is not single valued but has a Gaussian distribution around E 0 , with distribution function 15,16 …”

Investigation of the dielectric relaxation and the transport properties of porous silicates containing humidity

“…With the exception of the family of ionic crystals with extremely low concentration of impurities, it is commonly assumed that the activation energy is not single valued but distributes normally around E 0 , with distribution function [20,21]…”