A Singlet-RISM theory for solid/liquid interfaces Part I: uncharged walls

Area of Science:

• Computational chemistry
• Physical chemistry
• Statistical mechanics

Background:

• Understanding fluid behavior at interfaces is crucial in various scientific fields.
• Existing methods may have limitations in modeling complex fluid-solid interactions.
• The Reference Interaction Site Model (RISM) equation is a foundational theory for such problems.

Purpose of the Study:

• To develop a novel integral equation method for calculating fluid structure near a plane impenetrable wall.
• To extend the RISM equation to handle arbitrary interaction site model (ISM) fluids at solid/liquid interfaces.
• To compute wall-fluid density distributions and electrostatic profiles for water and electrolyte solutions.

Main Methods:

• Utilized a novel integral equation method based on the RISM equation.
• Incorporated several closure approximations for the integral equations.
• Numerically solved the equations to obtain site density and electrostatic profiles.
• Applied the method to pure water and aqueous electrolyte solutions near an uncharged soft wall.

Main Results:

• Calculated wall-fluid site density distributions for varying electrolyte concentrations.
• Determined charge density, field, and potential profiles at the interface.
• The method demonstrated capability for arbitrary ISM fluids.
• Obtained results showing reasonable agreement with computer simulation data.

Conclusions:

• The novel integral equation method provides an effective tool for studying fluid structure at interfaces.
• The approach is versatile, applicable to both pure solvents and electrolyte solutions.
• The findings validate the method's accuracy against established simulation techniques.