Kirkwood-Buff integrals for hard-core Yukawa fluids.

Area of Science:

• Physical Chemistry
• Statistical Mechanics
• Soft Matter Physics

Background:

• The Kirkwood-Buff (KB) theory provides a link between microscopic interactions and macroscopic thermodynamic properties of solutions.
• Understanding the behavior of one-component fluids is fundamental in statistical mechanics and physical chemistry.
• The hard-core Yukawa (HCY) model is a relevant system for studying fluid behavior with both repulsive and attractive forces.

Purpose of the Study:

• To investigate macroscopic properties of the one-component hard-core Yukawa (HCY) fluid using Kirkwood-Buff (KB) theory.
• To calculate Kirkwood-Buff integrals (KBIs) for both repulsive and attractive HCY fluids.
• To explore the relationship between local structure and global properties, including isothermal compressibility and chemical potential derivatives.

Main Methods:

• Employing Kirkwood-Buff (KB) theory to analyze HCY fluids.
• Utilizing classical density functional theory to compute radial distribution functions.
• Calculating Kirkwood-Buff integrals (KBIs) from the obtained radial distribution functions.

Main Results:

• Radial distribution functions and KBIs were computed for repulsive and attractive HCY fluids.
• Isothermal compressibility and chemical potential derivatives were determined.
• A transition in particle affinity within attractive HCY fluids was identified, with phase diagrams illustrating repulsive and attractive regions.

Conclusions:

• Kirkwood-Buff integrals offer a quantitative and reliable method for describing HCY fluid properties.
• The aggregated structure of HCY fluids can be effectively controlled by screening parameters, bulk density, and interaction energy.
• Phase diagrams based on particle affinity provide insights into the distinct behaviors of HCY fluids.