Capturing Weak Interactions in Surface Adsorbate Systems at Coupled Cluster Accuracy: A Graph-Theoretic Molecular...

Area of Science:

• Computational Chemistry
• Environmental Science
• Materials Science

Background:

• Interactions of organic matter with water surfaces are crucial for environmental and public health applications.
• Perfluorooctanoic acid (PFOA) is a persistent environmental pollutant that bioaccumulates, posing health risks.
• Accurate theoretical studies of these interactions require ab initio methods to capture long-range electronic properties.

Purpose of the Study:

• To demonstrate a novel graph-theoretic approach for molecular fragmentation to study weak interactions.
• To apply this method to understand perfluorooctanoic acid (PFOA) interactions on water surfaces.
• To develop an efficient and accurate computational method for extended systems.

Main Methods:

• A graph-theoretic molecular fragmentation technique is used to divide systems into locally interacting subsystems.
• Ab initio molecular dynamics simulations and potential energy surface calculations are performed on these subsystems.
• A transfer learning protocol with neural networks and k-means clustering optimizes computational efficiency.

Main Results:

• The graph-theoretic approach accurately captures critical weak interactions in extended systems.
• The method achieves significant computational cost reduction (over 10x) compared to traditional fragmentation.
• Results show excellent agreement with high-level coupled cluster theory for PFOA-water interfaces.

Conclusions:

• The developed graph-theoretic fragmentation method offers an efficient and accurate tool for studying organic-water interactions.
• This approach is valuable for environmental pollutant analysis, such as PFOA, and for understanding surface phenomena.
• The method provides a pathway for more accessible and detailed theoretical investigations of complex chemical systems.