Dielectric Properties of Nanoconfined Water: A Canonical Thermopotentiostat Approach

Abstract

We discuss how to include our recently proposed thermopotentiostat technique [Phys. Rev. Lett. 126, 136803 (2021)] into any existing ab initio molecular dynamics (AIMD) package. Using thermopotentiostat AIMD simulations in the canonical NVTΦ ensemble at constant electrode potential, we compute the polarization bound charge and dielectric response of interfacial water from first principles.

A molecular perspective on induced charges on a metallic surface

“…2 These fluctuations can be sampled in molecular simulations to determine how these components depend on the position with respect to the interface and/or on the width of the fluid slab for confined fluids. 3,5,7,9,57,58 The general picture emerging from these studies is a reduction in the permittivity in the vicinity of solid walls, consistently with experimental observations on confined water, 59 even though the microscopic origin of this reduction is not to be found in the molecular structure of interfacial water but rather in the frustration of collective long-range fluctuations. 11 The implications of a decrease in permittivity on other interfacial properties such as the capacitance or the electrokinetic response have also been investigated, in particular in the framework of suitably parameterized slab models.…”

ELECTRODE: An electrochemistry package for atomistic simulations

“…In a recent publication, Deißenbeck et al 25 have presented an thermo-potentiostat (TP) that takes into account the fluctuation-dissipation relation of electrode charges at a given voltage and temperature in an electronic circuit. They have also provided a TP implementation based on a uniform charge distribution using the scripting capability of LAMMPS.…”

“…They have also provided a TP implementation based on a uniform charge distribution using the scripting capability of LAMMPS. The ELECTRODE package provides an implementation that minimizes energy with respect to charge distribution and conforms to the formalism described in Deißenbeck et al 25 .…”

“…This work builds in part on an earlier work in which we showed how a particle-particle particle-mesh (P 3 M)-based calculation makes the electrostatic calculations of a CPM simulation much more efficient 24 . In addition to a few modifications of the CPM, moreover, this implementation provides a constrained charge method (CCM) and a thermo-potentiostat (TP) 25 . In order to capture the electronic response of non-ideal metals, a Thomas-Fermi (TF) model 26 is included.…”

Implicit Solvation Methods for Catalysis at Electrified Interfaces

“…The resulting decoupling of quantum chemistry and surface charging thus allows to control the accuracy of both scales roughly independently. While clearly inspired by the CHE, it is worthwhile to note that this approach is also closely related to traditional constant field calculations 37,39,373,[428][429][430][431][432][433][434][435][436] as interfacial fields are naturally proportional to surface charge, and it is correspondingly not surprising that latter calculations were also taken into consideration in the early developments of the CHE approximation. 373,374,428,429,433,434 Both the constant-potential 23,24,26,244,245,325,326,342,[419][420][421]437 and constant-charge 40,41,244,[424][425][426][427]430,431,436 approach enjoy present popularity, with the former also often denoted as fully grand-canonical (FGC) approach.…”