Variational field theory of macroscopic forces in coulomb fluids

Yury A Budkov; Petr E Brandyshev

doi:10.1063/5.0169795

Variational field theory of macroscopic forces in coulomb fluids

J Chem Phys. 2023 Nov 7;159(17):174103. doi: 10.1063/5.0169795.

Authors

Yury A Budkov^{1

2}, Petr E Brandyshev¹

Affiliations

¹ Laboratory of Computational Physics, HSE University, Tallinskaya st. 34, 123458 Moscow, Russia.
² Laboratory of Multiscale Modeling of Molecular Systems, G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Akademicheskaya st. 1, Ivanovo 153045, Russia.

PMID: 37916589
DOI: 10.1063/5.0169795

Abstract

Based on the variational field theory framework, we extend our previous mean-field formalism [Y. A. Budkov and A. L. Kolesnikov, JStatMech 2022, 053205.2022], taking into account the electrostatic correlations of the ions. We employ a general covariant approach and derive a total stress tensor that considers the electrostatic correlations of ions. This is accomplished through an additional term that depends on the autocorrelation function of the local electric field fluctuations. Utilizing the derived total stress tensor and applying the mechanical equilibrium condition, we establish a general expression for the disjoining pressure of the Coulomb fluids, confined in a pore with a slit-like geometry. Using this equation, we derive an asymptotic expression for the disjoining pressure in a slit-like pore with non-electrified conductive walls. Present theory is the basis for future modeling of the mechanical stresses that occur in electrode pores with conductive charged walls, immersed in liquid phase electrolytes beyond the mean-field theory.