Electrostatics of solvated systems in periodic boundary conditions

TL;DR

This paper extends continuum solvation methods to periodic boundary conditions in materials simulations, addressing electrostatic correction challenges and demonstrating their effectiveness through numerical tests on charged systems.

Contribution

It develops modifications to periodic-boundary electrostatic corrections for solvent environments within plane-wave DFT, enhancing simulation accuracy.

Findings

Corrected electrostatic interactions improve accuracy in solvated periodic systems.

Numerical tests show effectiveness of proposed correction methods.

Proper electrostatic treatment is crucial for charged systems in solution.

Abstract

Continuum solvation methods can provide an accurate and inexpensive embedding of quantum simulations in liquid or complex dielectric environments. Notwithstanding a long history and manifold applications to isolated systems in open boundary conditions, their extension to materials simulations --- typically entailing periodic-boundary conditions --- is very recent, and special care is needed to address correctly the electrostatic terms. We discuss here how periodic-boundary corrections developed for systems in vacuum should be modified to take into account solvent effects, using as a general framework the self-consistent continuum solvation model developed within plane-wave density-functional theory [O. Andreussi et al. J. Chem. Phys. 136, 064102 (2012)]. A comprehensive discussion of real-space and reciprocal-space corrective approaches is presented, together with an assessment of their ability to remove electrostatic interactions between periodic replicas. Numerical results for zero-dimensional and two-dimensional charged systems highlight the effectiveness of the different suggestions, and underline the importance of a proper treatement of electrostatic interactions in first-principles studies of charged systems in solution.