Self consistent tight binding model for dissociable water

Area of Science:

• Computational chemistry
• Physical chemistry
• Materials science

Background:

• Accurate modeling of water's electronic structure is crucial for understanding its properties.
• Existing models often struggle to capture electron behavior and dissociation dynamics.
• Developing efficient and accurate computational models for water remains a significant challenge.

Purpose of the Study:

• To develop a self-consistent tight-binding model for water.
• To enable fast, direct dynamics molecular dynamics calculations of fluid properties.
• To investigate the behavior of electrons, dissociation, and proton transport in water.

Main Methods:

• Development of a self-consistent tight-binding model.
• Parameterization using first-principles calculations on water monomers, dimers, and trimers.
• Molecular dynamics simulations of bulk liquid water and systems with dissociated molecules.

Main Results:

• Calculated radial distribution functions, phase diagram, and solvated proton structures show good agreement with experimental and first-principles data.
• The model accurately captures structural properties and the phase diagram of water.
• Simulated DC conductivity was higher than experimental values, but the proton to hydroxyl conductivity ratio closely matched experimental findings, suggesting a Grotthuss-like mechanism.

Conclusions:

• The developed tight-binding model provides a computationally efficient and accurate method for simulating water.
• The model successfully describes electronic properties, dissociation, and proton transport mechanisms.
• Further refinement of conductivity calculations is warranted, but the model shows promise for studying aqueous systems.