Polarizable Interaction Model for Liquid, Supercritical, and Aqueous Ammonia

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Materials Science

Background:

• Accurate simulation of ammonia properties is crucial for understanding chemical processes.
• Developing reliable computational models for ammonia and its solutions is an ongoing challenge.

Purpose of the Study:

• To develop and validate a polarizable model for ammonia.
• To assess the model's accuracy for ammonia clusters, liquid ammonia, and aqueous ammonia solutions.

Main Methods:

• Ab initio calculations (MP2 level) for small ammonia systems.
• Optimization of a polarizable model based on ab initio data.
• Molecular dynamics simulations of liquid and supercritical ammonia and aqueous solutions.

Main Results:

• The model accurately predicts structural and binding energies for ammonia clusters.
• It reproduces key properties of liquid ammonia (density, heat of vaporization, diffusion, etc.).
• The model captures the behavior of aqueous ammonia solutions, including density anomalies and solvation structures.

Conclusions:

• The developed polarizable ammonia model demonstrates excellent transferability across various phases and conditions.
• It provides a reliable tool for studying ammonia's behavior in diverse environments.
• The model offers insights into structural changes and solvation in aqueous ammonia mixtures.