Density functional theory for molecular liquids based on interaction site model and self-consistent integral...

Area of Science:

• Physical Chemistry
• Statistical Mechanics
• Computational Chemistry

Background:

• Classical density functional theory (DFT) is crucial for understanding liquid properties.
• Existing DFT methods for molecular liquids, like the Chandler et al. approach, have limitations.
• Accurate modeling of inhomogeneous polyatomic liquids remains a challenge.

Purpose of the Study:

• To introduce a novel classical density functional theory (DFT) for inhomogeneous polyatomic liquids.
• To establish radial density distributions around solute atomic sites as fundamental quantities.
• To develop a new theoretical framework for calculating site-site pair correlation functions (PCFs).

Main Methods:

• The proposed DFT is based on the grand canonical ensemble of a solute-solvent system.
• It utilizes radial density distributions around atomic sites as fundamental variables.
• The theory is combined with the reference interaction site model (RISM) to derive self-consistent integral equations.

Main Results:

• The new DFT scheme provides accurate self-consistent integral equations for site-site pair correlation functions (PCFs).
• Calculations were performed for Lennard-Jones dimer, HCl, and H2O molecular fluids.
• The obtained site-site PCFs show excellent agreement with Monte Carlo simulation data.

Conclusions:

• The novel classical DFT offers a powerful and accurate method for studying inhomogeneous polyatomic liquids.
• The focus on radial density distributions provides a new perspective in DFT for molecular liquids.
• This approach advances the computational modeling of complex fluid systems.