A transferable H2O interaction potential based on a single center multipole expansion: SCME

Area of Science:

• Computational chemistry
• Molecular dynamics
• Physical chemistry

Background:

• Accurate modeling of intermolecular interactions is crucial for understanding condensed phases.
• Existing water models often struggle with balancing accuracy and computational efficiency.

Purpose of the Study:

• To develop a transferable potential energy function for water-water interactions.
• To improve the accuracy and efficiency of molecular simulations of water.

Main Methods:

• Utilized a multipole expansion for electrostatic interactions with a single expansion center per molecule.
• Incorporated dipole and quadrupole polarizability.
• Parametrized repulsive, dispersion, and electrostatic terms using ab initio calculations and experimental data for water and ice Ih.

Main Results:

• The single-center multipole expansion up to hexadecapole showed good agreement with ab initio calculations.
• Simulations of liquid water using the new potential function yielded results that closely matched experimental data.
• The new potential demonstrated superior performance compared to some existing point-charge models.

Conclusions:

• The developed potential energy function provides an accurate and efficient description of water-water interactions.
• This model is suitable for simulating condensed phases, including liquid water and ice.
• The absence of point charges enhances computational speed in simulations.