Routes to the density profile and structural inconsistency
arXiv:2511.10433 · doi:10.1021/acs.jpcb.5c07785
Abstract
Classical density functional theory (DFT) is the primary method for investigations of inhomogeneous fluids in external fields. It requires the excess Helmholtz free energy functional as input to an Euler-Lagrange equation for the one-body density. A variant of this methodology, the force-DFT, uses instead the Yvon-Born-Green equation to generate density profiles. It is known that the latter are consistent with the virial route to the thermodynamics, while DFT is consistent with the compressibility route. In this work we will show an alternative DFT scheme using the Lovett-Mou-Buff-Wertheim (LMBW) equation to obtain density profiles, that are shown to be also consistent with the compressibility route. However, force-DFT and LMBW DFT can both be implemented using a closure relation on the level of the two-body correlation functions. This is proven to be an advantageous feature, opening the possibility of an optimisation scheme in which the structural inconsistency between different routes to the density profile is minimized. (Structural inconsistency is a generalization of the notion of thermodynamic inconsistency, familiar from bulk integral equation studies.) Numerical results are given for the density profiles of two-dimensional systems of hard-core Yukawa particles with a repulsive or an attractive tail, in planar geometry.
References in corpus (16)
- Fluid mixtures of parallel hard cubes
- Neural functional theory for inhomogeneous fluids: Fundamentals and applications
- Mean-Field Theory of Inhomogeneous Fluids
- Local order variations in confined hard-sphere fluids
- The smooth cut-off Hierarchical Reference Theory of fluids
- Integral equations for simple fluids in a general reference functional approach
- Recent developments of the Hierarchical Reference Theory of Fluids and its relation to the Renormalization Group
- Force density functional theory in- and out-of-equilibrium
- Machine learning of a density functional for anisotropic patchy particles
- Structural precursor to freezing: An integral equation study
- Why neural functionals suit statistical mechanics
- Learning Neural Free-Energy Functionals with Pair-Correlation Matching
- First-principles superadiabatic theory for the dynamics of inhomogeneous fluids
- Link between New Versions of the Hierarchical Reference Theory of Liquids and of the Non Perturbative Renormalization Group in Statistical Field Theory
- Combining integral equation closures with force density functional theory for the study of inhomogeneous fluids
- Machine Learning approaches to classical density functional theory