A molecular Debye-Hückel theory and its applications to electrolyte solutions: The size asymmetric case

Abstract

A molecular Debye-Hückel theory for electrolyte solutions with size asymmetry is developed, where the dielectric response of an electrolyte solution is described by a linear combination of Debye-Hückel-like response modes. As the size asymmetry of an electrolyte solution leads to a charge imbalanced border zone around a solute, the dielectric response to the solute is characterized by two types of charge sources, namely, a bare solute charge and a charge distribution due to size asymmetry. These two kinds of charge sources are screened by the solvent differently, our theory presents a method to calculate the mean electric potential as well as the electrostatic contributions to thermodynamic properties. The theory has been successfully applied to binary as well as multi-component primitive models of electrolyte solutions.

A multiple decay-length extension of the Debye–Hückel theory: to achieve high accuracy also for concentrated solutions and explain under-screening in dilute symmetric electrolytes

“…6 are beyond this point, so r(r) has an exponentially damped oscillatory decay. We then have complex k ¼ k 0 and the two terms in eqn (43) yield the expression for r in eqn (50). It is seen from the results from this equation, shown as the red dotted curve in the figure, that the agreement with the accurate HNC curve is about equally good as the results for the other concentrations.…”

“…Most of these approximations have been used to obtain thermodynamical quantities, distribution functions and/or the mean electrostatic potential. 15,16,27,28,[31][32][33]37,39,[42][43][44][45][46][47] Xiao and Song [48][49][50] have developed a linear theory that exploits all decay modes obtained in many of these approximations to calculate thermodynamical quantities for electrolytes. We will return to some of these linear, approximate theories later.…”

“…Approximations that explicitly deal with several decay modes have been proposed earlier. Xiao and Song [48][49][50] have developed a linear theory for electrolytes that they designate as a molecular Debye-Hückel theory (they use the acronym MDH, which should not be confused with MDH used in the current work). This theory, which is based on DIT, focuses on the decay modes of c i (r) as expressed in eqn (25) with several Yukawa function ‡ ‡ Eqn ( 24) can be formulated in several equivalent manners in DIT.…”

Studi Pengaruh Anion Asetat Terhadap Kelarutan Li2CO3 sebagai Dasar Recovery Litium pada Kondisi Terlindi Asam Asetat

“…Menurut teori kelarutan Debye-Hückel ketika kondisi mendekati ideal maka fungsi dari kelarutan didefinisikan aktivitas dari subtansi zat dalam pelarut sehingga koefisien aktivitas (γ) digunakan sebagai dasar interaksi ion terlarut [13]. Koefisien aktivitas sendiri juga dipengaruhi oleh kekuatan ion (I) yang merupakan nilai yang menunjukkan kemampuan garam terdisosiasi secara ideal di dalam larutan [14].…”

A Systematic Way to Extend the Debye–Hückel Theory beyond Dilute Electrolyte Solutions

“…Such a prescription has been applied successfully to various ionic fluids. [40][41][42][43][44] As the molecular DH theory is mainly developed for spherical ions and it remains an open question to deal with solutes beyond spherical geometry.…”