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

Abstract

The Poisson-Boltzmann and Debye-Hückel approximations for the pair distributions and mean electrostatic potential in electrolytes predict that these entities have one single decay mode with a decay length equal to...

Structure and thermodynamics in the linear modified Poisson-Boltzmann theories in restricted primitive model electrolytes

“…Here, we outline an argument why this is expected for a linear theory. Such an equivalence has recently been observed by Kjellander with regard to his Multiple-Decay Extended Debye-Hückel MDE-DH theory of electrolytes [44].…”

“…Similarly, in the analysis of numerically intensive theoretical problems (see for example, reference [52]) the use of LMPB analytical expressions as initial input in iterative processes can prove to be useful. Furthermore, the success of the LMPB approach in analyzing the thermodynamics of 1:1 valency systems makes this a potentially attractive method that can be used to explore more complex situations such as higher valency systems [44] and/or systems with a variable dielectric constant [53]. Studies of higher valency and mixed electrolyte systems would also be useful in order to see the limitations of the LMPB theories.…”

Bayesian unsupervised learning reveals hidden structure in concentrated electrolytes

“…Atomistic and coarse grained simulations have observed a screening length that seems to agree with the short-range 'structural force' observed in experiments, but not the long decay length [14]. Many theoretical approaches attempt to explain the data by introducing the idea of ion pairs [9,10] or effective dielectric constants [15]. The argument is that most cations and anions are bundled up as neutral pairs in concentrated electrolytes, thus the electrolyte comprises a low concentration of 'free' ions solvated in a liquid of effectively neutral 'paired' ions.…”

The Electrode-Electrolyte Interface from the perspective of Density Functional Theory

“…[60]. A very recent paper [98] introduced some new modifications/extensions of DH theory which make predictions for decay lengths. As far as we can tell, these are not significantly different from the results we present here.…”

“…Another obvious candidate is the omission of polarizability; this is absent completely in the RPM and is, at best, included approximately in some of the explicit-solvent models. An interesting approach was put forward by Kjellander [98,102,103], who shows that electrostatic screening and the static dielectric function ε(k), with wave-number k, are intimately coupled, such that the long-wavelength limit ε(0) equals the static dielectric constant only in the absence of ions, e.g in dipolar fluids or non-electrolytes, but not in their presence.…”