First-principles molecular dynamics simulations at solid-liquid interfaces with a continuum solvent.

Area of Science:

• Computational Chemistry
• Materials Science
• Physical Chemistry

Background:

• Continuum solvent models are standard in electronic structure calculations but lack implementations for solid-liquid interfaces.
• Existing models struggle with interfacial regions due to density-dependent dielectric functions causing convergence issues.

Purpose of the Study:

• To develop a robust continuum solvent model for molecular dynamics simulations at solid-liquid interfaces within a DFT framework.
• To investigate the acid-base equilibrium at the titanium dioxide (TiO2)-water interface.

Main Methods:

• Developed a continuum solvent approach using plane-wave basis sets and periodic boundary conditions.
• Redefined the dielectric medium as a function of atomic coordinates for improved convergence.
• Utilized a multigrid method to solve the Poisson problem efficiently.
• Performed Car-Parrinello molecular dynamics simulations.

Main Results:

• Achieved good convergence and conserved energy during molecular dynamics simulations of solid-liquid interfaces.
• Demonstrated the model's capability to investigate interfacial phenomena at a moderate computational cost.
• Applied the scheme to study the acid-base equilibrium at the TiO2-water interface.

Conclusions:

• The proposed continuum solvent model enables efficient and accurate molecular dynamics simulations at solid-liquid interfaces.
• The model provides a valuable tool for understanding the molecular mechanisms governing interfacial chemistry, such as acid-base equilibria on oxide surfaces.