Correlation between the electron solvation time and the solvent dielectric relaxation times τ2 and τL1 in liquid alcohols and water: towards a universal concept of electron solvation?

1997 ◽  
Vol 75 (10) ◽  
pp. 1310-1314 ◽  
Author(s):  
Jean-Paul Jay-Gerin
Keyword(s):  
Relaxation Time ◽  
Simple Model ◽  
Dielectric Relaxation ◽  
Hybrid Model ◽  
Relaxation Times ◽  
Close Similarity ◽  
Dielectric Relaxation Time ◽  
Polar Liquids ◽  
Electron Solvation ◽  
Linear Alcohols

A simple model of electron solvation in polar liquids is presented, in which we attempt to link the electron solvation time τs to τ2, the time for reorientation of monomeric molecules, and to τL1, the longitudinal dielectric relaxation time of the solvent. It is shown that this model, which is suggested by the so-called hybrid model of electron solvation previously described for methanol, can satisfactorily account for electron solvation in all polar liquids, including linear alcohols (methanol to decanol), 1,2-ethanediol, H2O, and D2O, for which data are available from the literature. A close similarity is indeed obtained between our calculated values of τs and those measured experimentally. The observation of such a correlation supports a universal concept of electron solvation. Keywords: polar liquids, electron solvation time, solvent dielectric relaxation times, universal concept of electron solvation.

scholarly journals An Empirical Relation for the Evaluation of the Dielectric Relaxation Time of Certain Polar Liquids Using a Single Microwave Frequency

1974 ◽  
Vol 27 (1) ◽  
pp. 87 ◽  
Author(s):  
BS Sarma ◽  
V Venkateswara Rao
Keyword(s):  
Experimental Data ◽  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Concentration Factor ◽  
Empirical Relation ◽  
Microwave Frequency ◽  
Dielectric Constants ◽  
Dielectric Relaxation Time ◽  
Polar Liquids

An empirical relation is proposed for the determination of the dielectric relaxation time .. of polar liquids with nearly spherical molecules from measurements of the dielectric constants at a single microwave frequency. The relation is obtained by introducing a concentration factor as a parameter in the expression for .. derived by Eyring et al. (1941). Its validity for suitable polar liquids is demonstrated by comparison of results with previously reported values. Thermodynamic parameters for a number of liquids at various concentrations have also been evaluated from experimental data using the relation.

Using an Expectation—Maximization Algorithm to Obtain Dielectric Relaxation-Time Spectra of Aqueous Montmorillonite Clay Suspensions

2002 ◽  
Vol 56 (11) ◽  
pp. 1470-1474 ◽  
Author(s):  
Stephen E. Bialkowski ◽  
Lynn Dudley ◽  
Dani Or
Keyword(s):  
Relaxation Time ◽  
Em Algorithm ◽  
Dielectric Relaxation ◽  
Expectation Maximization ◽  
Relaxation Times ◽  
Expectation Maximization Algorithm ◽  
Complex Impedance ◽  
Dielectric Relaxation Time ◽  
Ill Posed ◽  
Clay Suspensions

Determination of relaxation-time distributions from dielectric spectra of complex impedance or dielectric permittivity remains a challenge. This problem is one of a wider class of ill-posed inverse problems where the measurement is a superposition or convolution of functions containing the sought-after information. An expectation–maximization (EM) algorithm is shown to be useful for obtaining dielectric relaxation-time distributions from impedance data. This algorithm is stable and converges to realistic relaxation-time spectra without the need for constraints or initial values. The implementation used herein updates expectations in an iterative multiplication step. The models and basic assumptions of impedance spectroscopy are outlined in the first part of this paper. Frequency-dependent impedance measurements are obtained for calibration samples and saturated montmorillonite clays. The EM algorithm is subsequently used to determine the dielectric relaxation times. The dielectric relaxation-time spectra allow facile interpretation of otherwise complicated impedance.

Dielectric relaxation, viscosity and freezing

1957 ◽  
Vol 240 (1220) ◽  
pp. 101-107 ◽  
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Solid State ◽  
Dielectric Relaxation ◽  
Simple Relation ◽  
Experimental Results ◽  
Organic Liquids ◽  
Dielectric Relaxation Time ◽  
Polar Liquids ◽  
Molecular Radius

It is shown that polar liquids may be divided into two classes according to whether or not the rotation of the dipoles is prevented by solidification. For liquids belonging to the first class, and having rigid molecules, an equation similar to Debye’s can be used to relate the dielectric relaxation time and the viscosity. This equation does not involve the ‘molecular radius’ which has always made the interpretation of Debye’s equation uncertain, and it can, in consequence, be used to determine from the experimental results how the ratio of the microscopic to the macroscopic relaxation time ( ז/ז ') depends on the static dielectric con­stant. The theory has been applied to a number of organic liquids of rigid molecular struc­ture, and indicates that the dependence of ז/ז ' on the dielectric constant is best expressed by Powles’s equation ז/ז ' = (2∊ 0 + ∊ ∞ )/3∊ 0 . For liquids belonging to the second class no simple relation between dielectric relaxation time and viscosity can be expected, but it may be possible to relate the relaxation time in some way to the transition which occurs in the solid state, in which the freedom of dipole rotation is lost.

Zur Molekülbewegung in Flüssigkeiten und Lösungen I

1965 ◽  
Vol 20 (11) ◽  
pp. 1391-1400 ◽  
Author(s):  
K. D. Kramer ◽  
W. Müller-Warmuth ◽  
N. Roth
Keyword(s):  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Hard Spheres ◽  
Double Resonance ◽  
Relaxation Times ◽  
Translational Diffusion ◽  
Magnetic Interactions ◽  
Proton Relaxation ◽  
Dielectric Relaxation Time ◽  
Correlation Times

The magnetic proton relaxation behaviour of free radical solutions of diethylether and diethoxyethane has been studied by a nuclear-electron double resonance method. The dielectric relaxation in the solvents has also been determined from a study of the frequency dependance of the complex dielectric constant.The motional properties of the spin-carrying molecules which govern the magnetic interactions between different spin species are described by the model of randomly diffusing hard spheres. The time dependence is assumed to result from a combination of the relative translational diffusion of the spheres and the random rotational motions of complexes of spheres. Expressions and curves are given for the nuclear electron coupling parameter of dynamic nuclear polarisation and its frequency dependence. The comparison with experimental data taken at four different frequencies corresponding to magnetic fields of 15, 175, 1070 and 3230 gauss confirms the absence of scalar interactions and yields limits for the predominating translational diffusion. Correlation times at different temperatures and distances of closest approach of spins are evaluated.The dielectric studies in ether yield a single relaxation time which is attributed to the orientation of the molecule as a whole. Diethoxyethane has a spectrum of dielectric relaxation times. The dielectric relaxation times and also their activation energies are smaller than the correlation times obtained by magnetic measurements. The viscosity is more closely related to the translational diffusion of molecules than to the dielectric relaxation time. The results are discussed in terms of the different mechanisms of motion.

Viscosity and dielectric relaxation time in polar liquids

1966 ◽  
Vol 5 (3) ◽  
pp. 232-234
Author(s):  
S. Mallikarjun ◽  
Nora E. Hill
Keyword(s):  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Dielectric Relaxation Time ◽  
Polar Liquids

Dielectric relaxation time and dipole moment of isometric butanols in benzene solutions.

1983 ◽  
Vol 26 (2) ◽  
pp. 77-84 ◽  
Author(s):  
S.M. Khameshara ◽  
M.S. Kavadia ◽  
M.S. Lodha ◽  
D.C. Mathur ◽  
V.K. Vaidya
Keyword(s):  
Dipole Moment ◽  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Dielectric Relaxation Time
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