Potential Energy Surfaces Sampled in Cremer-Pople Coordinates and Represented by Common Force Field Functionals for...

Area of Science:

• Computational Chemistry
• Molecular Modeling
• Physical Chemistry

Background:

• Molecular conformations significantly influence chemical and physical properties.
• Understanding these conformations is crucial for predicting molecular behavior.

Purpose of the Study:

• To comprehensively sample and characterize the conformational space of cyclic molecules.
• To develop accurate analytical force field (FF) models for potential energy surfaces (PESs).

Main Methods:

• Utilized Cremer-Pople coordinates for thorough conformational sampling of 22 four-, five-, and six-membered ring molecules.
• Identified known and novel conformers, generating 1504 (4-membered), 5576 (5-membered), and 13509 (6-membered) structures.
• Fitted conformational data to analytical FF functional forms to represent PESs.

Main Results:

• Successfully identified a comprehensive set of conformers for each ring size.
• Demonstrated that essential FF functional forms capture general PES features.
• Showed significant accuracy improvement by incorporating torsion-bond and torsion-angle coupling terms.

Conclusions:

• Accurate representation of molecular PESs requires advanced FF functional forms, including coupling terms.
• The developed FF models achieve high accuracy, with R-squared values near 1.0 and low mean absolute energy errors (<0.3 kcal/mol).
• This work provides a robust framework for conformational analysis and force field development in cyclic systems.