Function-Space-Based Solution Scheme for the Size-Modified Poisson–Boltzmann Equation in Full-Potential DFT

Modelling the electrolyte at the electrochemical interface remains a major challenge in ab initio simulations of charge transfer processes at surfaces. Recently, the development of hybrid polarizable continuum models/ab initio models have allowed for the treatment of solvation and electrolyte charge in a computationally efficient way. However, challenges remain in its application. Recent literature has reported that large cell heights are required to reach convergence, which presents a serious computational cost. Furthermore, calculations of reaction energetics require costly iterations to tune the surface charge to the desired potential. In this work, we present a simple capacitor model of the interface that illuminates how to circumvent both of these challenges. We derive a correction to the energy for finite cell heights to obtain the large cell energies at no additional computational expense. We furthermore demonstrate that the reaction energetics determined at constant charge are easily mapped to those at constant potential, which eliminates the need to apply iterative schemes to tune the system to a constant potential. These developments together represent more than an order of magnitude reduction of the computational overhead required for the application of polarizable continuum models to surface electrochemistry.

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“…We recall from Eq. (9), that at constant charge the expression for the change in energy becomes Equation (18):…”

Section: Mapping Energetics At Constant Charge To Constant Potentialmentioning

confidence: 99%

Practical Considerations for Continuum Models Applied to Surface Electrochemistry

et al. 2019

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“…In addition to being applied to molecular liquids, the continuum approximation has found fertile ground in the modeling of ionic solutions. [19,33,37,38,50,65,69] In this case, a continuum classical description is also adopted to model the distribution of electrolyte species in the liquid solution. This additional component allows having a more accurate description of solvated charged systems, that more strongly interact with the charged components of an electrolyte.…”

Section: The Continuummentioning

confidence: 99%

“…This contribution was later acquired by several other models, for example, Refs. [34,64,65,84] Defining the interface in terms of just the electronic density may present some significant drawbacks in specific applications. One critical limitation is encountered when using approximate techniques to handle core-electrons, such as the pseudo-potential approach commonly adopted in condensed-matter simulations based on delocalized basis sets.…”

Section: Atomic Vs Electronic Interfacesmentioning

confidence: 99%

“…Implementations of these approaches, in particular of the FG model and its direct descendants, have been reported for Quantum ESPRESSO, [52,53] BigDFT, [3,54,55] FHI-Aims, ONETEP, [56] CP2K, [6] GPAW, [57] and VASP. [2,[58][59][60] Among these recent developments, publicly available distributions of continuum embedding approaches have been released for Quantum ESPRESSO via the Environ module, [61] for VASP through the VASPsol package, [62] in the J-DFTx code, [47] in the CP2K package, [63,64] in the FHI-Aims package, [65][66][67] and for ONETEP exploiting the DM_LG library. [68] This review aims at covering the basic physical and numerical aspects of these models, their specific features and their main differences with respect to state-of-the-art continuum solvation models in quantum-chemistry simulations.…”

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confidence: 99%

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Continuum embeddings in condensed‐matter simulations

Andreussi

Fisicaro

2018

Int J of Quantum Chemistry

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Continuum models have a long tradition in computational chemistry, where they have provided a compact and efficient way to characterize environment effects in quantum-mechanical simulations of solvated systems. Fattebert and Gygi pioneered the development of continuum dielectric embedding schemes for periodic systems and their seamless extension toward molecular dynamics simulations. Following their work, continuum embedding approaches in condensedmatter simulations have thrived. The possibility to model wet and electrified interfaces, with a reduced computational overhead with respect to isolated systems, is opening new perspectives in the characterization of materials and devices. Important applications of these new techniques are in the field of catalysis, electro-chemistry, electro-catalysis, etc. Here we will address the main physical and computational aspects of continuum embedding schemes recently developed for condensed-matter simulations, underlying their peculiarities and their differences with respect to the quantum-chemistry state-of-the-art.condensed matter, continuum models, electro-chemistry, materials, solvation 1 | INTRODUCTION An embedding liquid environment can substantially affect the electronic properties, geometries and spectroscopic responses of the embedded system. Dealing with this kind of effects is a difficult computational task, due to the multiscale nature of the system. A brute force approach to handle these effects would require including all of the solvent atomistic details in the quantum-mechanical (QM) calculation of the solvated system. The total number of degrees of freedom, in particular the number of electrons that need to be described in a first-principles calculation, can thus increase by orders of magnitude. As a result, a calculation that would be feasible in vacuum can easily become untreatable in solution. Moreover, statistical sampling and averaging of the results over different configurations of the liquid would be required, thus further increasing the computational cost of such an approach. These limitations have motivated the development of incredibly powerful simulation programs, [1][2][3] able to take advantage of the rapid evolution of scientific computing hardware and software, for example, by fully exploiting parallel and hybrid architectures. Regardless of its computational feasibility, the explicit description of liquid environments may also suffer from some well-known limitations of current state-of-the-art ab initio methods, in particular regarding their structural [4][5][6][7] and dielectric [8][9][10] properties.On the other hand, when looking at the properties of a solvated system, it is often the case that the detailed effects caused by solute-solvent interactions are less important than the intrinsic properties of the solute. If this is the case, one can exploit a hierarchical approach, where solvent degrees of freedom are treated with a computationally less expensive technique, but are coupled with an highly accurate description of the solvated system...

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“…Despite its importance for various chemical and biological processes, such as fuel cells or ion channels,, and the extensive research into this direction over the years, the exact nature of the electric double layer (EDL) is still not fully understood at the molecular level. Attempts to accurately model the electrode electrolyte interface are often carried out with the help of continuum models to avoid the computational costs of explicitly including a large amount of electrolyte molecules. The Poisson‐Boltzmann theory is a simple yet powerful tool to model aqueous ion solutions.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Investigation of the Dielectric Decrement of Ion Solutions

Pache

Schmid

2018

ChemElectroChem

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Molecular dynamics simulations, using a classical force field model, have been used to determine the dependence of the static relative dielectric constant of ion solutions with respect to the nature and concentration of the ions and the field strength. The experimentally observed effect of a reduction of the dielectric permittivity due to solvated ions is known as dielectric decrement. We used both the polarization fluctuation at zero field and the constant dielectric displacement method for finite fields to determine the dielectric constant of the bulk solution. All the experimentally observed tendencies of the dielectric decrement could be qualitatively reproduced. The analysis of different solute solvent radial distribution functions indicate that the dielectric decrement arises from the competition between the macroscopic electric field and the local water‐ion interaction. The results suggest that the electric field eventually manages to overcome the local molecular interactions, breaking up the structure of the solvation shell and thus lowering the ion's effect on the dielectric constant. This effect seems to correlate with the solvation energy of the individual ions as well as the type of counter ion, indicating that also long range interactions might play a role. The results can be used to improve especially continuum electrolyte models, used to study electrochemical interfaces, where currently the dielectric decrement is generally not included.

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Function-Space-Based Solution Scheme for the Size-Modified Poisson–Boltzmann Equation in Full-Potential DFT

Cited by 75 publications

References 98 publications

Practical Considerations for Continuum Models Applied to Surface Electrochemistry

Practical Considerations for Continuum Models Applied to Surface Electrochemistry

Continuum embeddings in condensed‐matter simulations

Molecular Dynamics Investigation of the Dielectric Decrement of Ion Solutions

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