Many-Body Contributions in Water Nanoclusters

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Materials Science

Background:

• Many-body interactions in water are crucial but computationally challenging for atomistic models.
• Polarizable models explicitly include many-body potentials but are computationally expensive.
• Current methods often treat many-body interactions as corrections rather than explicit components.

Purpose of the Study:

• To evaluate the relevance of different coordination shells in many-body water interactions.
• To determine the minimum number of bodies required for accurate energy and structural approximation.
• To identify strategies for developing computationally efficient yet reliable many-body water potentials.

Main Methods:

• Calculation of global energy minima and configurations for water nanoclusters (up to 20 molecules).
• Systematic evaluation of many-body interaction contributions from successive coordination shells.
• Validation across three distinct polarizable water models: Dang-Chang, MB-pol, and Kozack-Jordan.

Main Results:

• Including only the first coordination shell (five-body term) approximates the global energy minimum within 5%.
• The first coordination shell accurately captures the essential structural features of the nanoclusters.
• This approximation holds consistently across the tested polarizable water models.

Conclusions:

• The first coordination shell's contribution is dominant and sufficient for accurate many-body water simulations.
• A simplified approach focusing on the first coordination shell can significantly reduce computational cost.
• This research paves the way for developing efficient and accurate polarizable many-body water potentials.