@article {7146,
title = {DIELECTRIC-RELAXATION OF ELECTROLYTE-SOLUTIONS},
journal = {Journal of Chemical Physics},
volume = {94},
number = {10},
year = {1991},
note = {ISI Document Delivery No.: FL001Times Cited: 29Cited Reference Count: 49},
month = {May},
pages = {6795-6806},
type = {Article},
abstract = {The dielectric relaxation theory of electrolyte solutions is formulated in terms of solvent-solvent, ion-ion, and ion-solvent van Hove time correlation functions. General wave vector frequency-dependent expressions are given for the longitudinal components of the relevant (i.e., polarization-polarization, current-current, current-polarization, polarization-current) time correlation functions and of the susceptibility, dielectric, and conductivity tensors. The Kerr theory relating the distinct and self parts of the van Hove functions is extended to mixtures of molecular fluids and solved explicitly in the k {\textendash}> 0 limit for solutions of spherical ions (assuming that the self part of the van Hove functions is given by Fick{\textquoteright}s law) immersed in polar solvents. At this level of theory, the van Hove functions, the time correlation functions and the susceptibilities are all found to depend upon coupled ion-solvent motion. However, the dynamical coupling terms are shown to cancel exactly in the final expressions for the conductivity and dielectric constant yielding relatively simple results. Specifically, the conductivity obtained is independent of frequency and is related to the self diffusion constants of the ions by the Nernst-Einstein expression. If a spherical diffusor model is chosen for the solvent, then the frequency-dependent dielectric constant is given by a Debye-type formula with a concentration dependent relationship connecting the Debye and self reorientational relaxation times of the solvent. These results are discussed in the context of previous theories and experimental observations. It is shown that, although obviously oversimplified, the present theory does qualitatively predict the correct concentration dependence of the observed relaxation times for a number of salt solutions.},
keywords = {DIPOLAR LIQUIDS, DISPERSION, FLUIDS, friction, INVARIANT EXPANSION, LIQUIDS, MEAN SPHERICAL MODEL, MOLECULAR THEORY, ORNSTEIN-ZERNIKE EQUATION, POLAR, TRANSLATIONAL DIFFUSION},
isbn = {0021-9606},
url = {://A1991FL00100048},
author = {Wei, D. Q. and Patey, G. N.}
}
@article {7145,
title = {DIELECTRIC-RELAXATION OF LIQUID-MIXTURES},
journal = {Journal of Chemical Physics},
volume = {94},
number = {10},
year = {1991},
note = {ISI Document Delivery No.: FL001Times Cited: 15Cited Reference Count: 41},
month = {May},
pages = {6785-6794},
type = {Article},
abstract = {General expressions in terms of van Hove time correlation functions are given for the wave vector frequency-dependent dielectric function of multicomponent mixtures. The van Hove functions are obtained by applying the Kerr approximation and the dielectric relaxation at zero wave vector is considered in detail. At this level of theory, the frequency-dependent dielectric constant depends upon the self-reorientational correlation times of the various species involved and upon the equilibrium pair correlation functions. It is shown that if the self-correlation times are assumed to be given by the Stokes-Debye relationship, and if the equilibrium direct correlation functions obey certain relatively weak conditions, then for particles of equal size (i.e., the self-correlation times are the same for all species) the dielectric relaxation behavior can be described by a simple Debye formula with a single concentration-dependent relaxation time. This observation is independent of the number of components, of the concentration, and of the molecular dipole moments of the different species present. It may help explain why for some binary mixtures of polar molecules experimental measurements indicate only a single relaxation channel. The exact Kerr result for binary mixtures is expressed explicitly as the sum of two Lorentzians, and some numerical results are given for solutions of dipolar hard spheres of different diameter.},
keywords = {CONSTANT, DIPOLAR LIQUIDS, DYNAMICS, ELECTROLYTE-SOLUTIONS, INVARIANT EXPANSION, MEAN SPHERICAL MODEL, MOLECULAR LIQUIDS, ORNSTEIN-ZERNIKE EQUATION, SOLVATION, TRANSLATIONAL DIFFUSION},
isbn = {0021-9606},
url = {://A1991FL00100047},
author = {Wei, D. Q. and Patey, G. N.}
}