Molecular theory of solvated ion dynamics. III. The kinetic dielectric decrement

Hubbard, John H.; Colonomos, Peter; Wolynes, Peter G.

doi:10.1063/1.438622

Cited by 125 publications

(87 citation statements)

References 21 publications

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“…(11), the so-called dielectric decrement, is the quantity discussed in theoretical concepts of solvation (2,5,35,(45)(46)(47)(48) and kinetic depolarization (49)(50)(51)(52). It is obvious that precise measurements at low electrolyte concentrations are required for the determination of reliable values of 3.…”

Section: Discussion Of Permittivities and Relaxation Times General Asmentioning

confidence: 99%

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Dielectric properties of nonaqueous electrolyte solutions

Barthel¹,

Buchner²

1986

Pure and Applied Chemistry

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-High frequency permittivity of non-aqueous electrolyte solutions and their solvents is discussed in the framework of time domain and frequency domain methods. Evaluation of data is performed on the basis of models presupposing one or more relaxation processes. Depression of the solvent permittivity, relaxation times of the solvent molecules, and dispersion amplitudes and relaxation times of ion-pair relaxation are investigated with regard to actual theories underlying these phenomena. Information is obtained on structural and dynamical properties of classes of electrolyte solutions based on rotic H-bonding, dipolar aprotic, and low permittivity solvents and mixtures of solvents.

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Section: Discussion Of Permittivities and Relaxation Times General Asmentioning

confidence: 99%

“…(51), permits the calculation of depolarization factors from reduced ionic decrements A+ and A and transference numbers t and t_ (+, cation; -, anion).…”

Section: Discussion Of Permittivities and Relaxation Times General Asmentioning

confidence: 99%

Dielectric properties of nonaqueous electrolyte solutions

Barthel¹,

Buchner²

1986

Pure and Applied Chemistry

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“…This consists in applying a constant (fictitious) electric field acting only on ions, and in measuring the induced polarization in water by the ion flow. This method realizes directly the thought experiment proposed by Hubbard and co-workers 25 to explain the first dynamic mechanism for the decrement. This NEMD approach has obvious advantages over the linear-response approach: relatively high fields can be used to increase the signal-tonoise ratio, and no extrapolation procedure is needed.…”

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confidence: 99%

“…The contribution coming from the cross-correlation C wi is large and positive, in open contrast to the prediction of a kinetic decrement by the Hubbard-Onsager mechanism. In the continuum approximation, i.e., in the limit of infinite dilution and large ionic radius, this decrement can be estimated 25 as HO,cont = −8πτ wT σ ( 0 − ∞ )/3 0 , where σ , 0 , and ∞ are the static conductivity, static permittivity, and infinite frequency dielectric permittivity of the solution, and τ wT is the (Debye-like) relaxation time of the solvent. Note that the single Debye relaxation in the Hubbard-Onsager model is an approximation, as the solvent relaxation in this case would be better described by either a superposition of Debye processes or by a Cole-Cole function.…”

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confidence: 99%

“…The reliability of the KBFF results offers the opportunity to test quantitatively the Hubbard-Onsager continuum theory 2,29 and the Hubbard-Colonomos-Wolynes molecular theory 25 for the kinetic decrement. Obtaining a precise estimate of the kinetic decrement from the analysis of the spectrum C wi (ω), however, can be computationally quite demanding, especially if the static contribution is small.…”

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Communication: Kinetic and pairing contributions in the dielectric spectra of electrolyte solutions

Sega

Kantorovich

Holm

et al. 2014

The Journal of Chemical Physics

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Understanding dielectric spectra can reveal important information about the dynamics of solvents and solutes from the dipolar relaxation times down to electronic ones. In the late 1970s, Hubbard and Onsager predicted that adding salt ions to a polar solution would result in a reduced dielectric permittivity that arises from the unexpected tendency of solvent dipoles to align opposite to the applied field. So far, this effect has escaped an experimental verification, mainly because of the concomitant appearance of dielectric saturation from which the Hubbard-Onsager decrement cannot be easily separated. Here we develop a novel non-equilibrium molecular dynamics simulation approach to determine this decrement accurately for the first time. Using a thermodynamic consistent allatom force field we show that for an aqueous solution containing sodium chloride around 4.8 Mol/l, this effect accounts for 12% of the total dielectric permittivity. The dielectric decrement can be strikingly different if a less accurate force field for the ions is used. Using the widespread GROMOS parameters, we observe in fact an increment of the dielectric permittivity rather than a decrement. We can show that this increment is caused by ion pairing, introduced by a too low dispersion force, and clarify the microscopic connection between long-living ion pairs and the appearance of specific features in the dielectric spectrum of the solution.

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