Revisiting the Charged Shell Model: A Density Functional Theory for Electrolytes.

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Statistical Mechanics

Background:

• Classical density functional theory (DFT) is a powerful tool for studying charged systems.
• Existing DFT models for inhomogeneous charged hard-sphere fluids often rely on approximations like the mean spherical approximation (MSA).
• Accurate prediction of ion density profiles and thermodynamic properties requires precise modeling of hard-core and electrostatic interactions.

Purpose of the Study:

• To develop a more accurate density functional theory (DFT) for inhomogeneous charged fluids.
• To incorporate an exact charged shell model into DFT for improved electrostatic interaction calculations.
• To provide analytic expressions for shell interaction potentials and thermodynamic quantities.

Main Methods:

• Rebuilding DFT based on the exact charged shell model.
• Utilizing fundamental measure theory (FMT) for hard-core interactions.
• Analyzing structural and thermodynamic properties of bulk and inhomogeneous electrolyte systems.

Main Results:

• Analytic expressions for shell interaction potential and thermodynamic quantities were derived.
• The developed DFT accurately predicts density profiles of ions and satisfies thermodynamic sum rules.
• Structural and thermodynamic properties of electrolyte systems were successfully analyzed.

Conclusions:

• The new DFT approach based on the exact charged shell model offers improved accuracy for charged fluid systems.
• The developed theoretical framework and associated software (Atif) provide valuable tools for researchers.
• This work advances the understanding and computational modeling of inhomogeneous electrolyte behavior.