A note on accurate pressure calculations of Coulomb systems with periodic boundary conditions

Fuente: arXiv
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Main Authors: Li, Lei, Liang, Jiuyang, Xu, Zhenli
Format: Preprint
Published: 2024
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author Li, Lei
Liang, Jiuyang
Xu, Zhenli
author_facet Li, Lei
Liang, Jiuyang
Xu, Zhenli
contents In this note, we address some issues concerning the accurate pressure calculation of Coulomb systems with periodic boundary conditions. First, we prove that the formulas for the excess part of the pressure with Ewald summation also reduce to the ensemble average of one-third of the ratio between the potential energy and the volume so that the comments on our previous work in a recent paper by [Onegin~\emph{et al}.,~J. Phys. A: Math.~Theor.~57 (2024) 205002] are incorrect. Second, we demonstrate that in charge non-neutral systems, the pressure expression must be corrected to include interactions with the neutralizing background. This addresses the issues about pressure computation in LAMMPS raised in the paper by Onegin {\it et al.}. Numerical experiments are performed to verify that the pressure obtained via Ewald summation with corrected terms agrees with the average pressure using thermodynamics for the non-neutral OCP system, and are independent of the splitting parameter in the Ewald summation.
format Preprint
id arxiv_https___arxiv_org_abs_2406_05627
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A note on accurate pressure calculations of Coulomb systems with periodic boundary conditions
Li, Lei
Liang, Jiuyang
Xu, Zhenli
Computational Physics
Chemical Physics
In this note, we address some issues concerning the accurate pressure calculation of Coulomb systems with periodic boundary conditions. First, we prove that the formulas for the excess part of the pressure with Ewald summation also reduce to the ensemble average of one-third of the ratio between the potential energy and the volume so that the comments on our previous work in a recent paper by [Onegin~\emph{et al}.,~J. Phys. A: Math.~Theor.~57 (2024) 205002] are incorrect. Second, we demonstrate that in charge non-neutral systems, the pressure expression must be corrected to include interactions with the neutralizing background. This addresses the issues about pressure computation in LAMMPS raised in the paper by Onegin {\it et al.}. Numerical experiments are performed to verify that the pressure obtained via Ewald summation with corrected terms agrees with the average pressure using thermodynamics for the non-neutral OCP system, and are independent of the splitting parameter in the Ewald summation.
title A note on accurate pressure calculations of Coulomb systems with periodic boundary conditions
topic Computational Physics
Chemical Physics
url https://arxiv.org/abs/2406.05627