Anisotropic Interface Continuum Solvation Model and the Finite-Element Anisotropic Poisson Solver

Area of Science:

• Computational chemistry
• Materials science
• Physical chemistry

Background:

• Simulating liquid behavior at solid-liquid interfaces requires accounting for anisotropic dielectric properties.
• Existing models often simplify these complex interfacial interactions.

Purpose of the Study:

• To develop and implement an Anisotropic Interfacial Continuum Solvation (AICS) model.
• To accurately capture distinct in-plane and out-of-plane dielectric constants and their spatial variations near interfaces.
• To enable more realistic simulations of interfacial phenomena.

Main Methods:

• Developed the AICS model with distance- and electron density-dependent dielectric functions.
• Derived analytical expressions for electrostatic Kohn-Sham potential and atomic forces.
• Implemented AICS and analytical derivatives in the CP2K software package.
• Developed a parallel finite-element anisotropic Poisson solver (FEAPS) using FEniCSx.
• Validated analytical forces and benchmarked electrostatic potentials against established methods.

Main Results:

• The AICS model and FEAPS solver were successfully implemented and validated.
• Simulations near the Ag(111) surface showed enhanced in-plane and reduced out-of-plane dielectric functions.
• Calculated work functions and electrostatic potentials exhibited more pronounced shifts and spatial modulation under anisotropic conditions.
• The adsorption geometry of OH* was optimized, showing a tilt towards the surface plane.

Conclusions:

• The AICS model provides a more accurate representation of anisotropic solvation at interfaces.
• Anisotropic dielectric properties significantly influence interfacial energetics and molecular adsorption.
• This work enables more precise computational studies of interfacial phenomena in various chemical and physical systems.