Partial Charges in Periodic Systems: Improving Electrostatic Potential (ESP) Fitting via Total Dipole Fluctuations
Andrea Gabrieli1, Marco Sant1, Pierfranco Demontis1
1Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari , Via Vienna 2, 07100 Sassari, Italy.
Journal of Chemical Theory and Computation
|November 18, 2015
Summary
Two new methods, D-REPEAT and M-REPEAT, improve partial charge generation for molecular simulations. The combined DM-REPEAT method offers stable, accurate atomic charges for periodic systems, addressing the buried atom problem.
Area of Science:
- Computational chemistry
- Materials science
Background:
- Accurate partial charges are crucial for molecular simulations of periodic structures.
- Existing methods like REPEAT (Repeating Electrostatic Potential Extracted Atomic) have limitations.
Purpose of the Study:
- To develop improved methods for generating accurate partial charges for periodic systems.
- To address the challenge of accurately assigning charges to buried atoms in molecular simulations.
Main Methods:
- Introducing D-REPEAT: simultaneous fitting of electrostatic potential (ESP) and total dipole fluctuations (TDF).
- Introducing M-REPEAT: fitting multiple ESP configurations concurrently.
- Combining D-REPEAT and M-REPEAT into the DM-REPEAT method.
Main Results:
- DM-REPEAT yields remarkably stable partial charges across various fitting regions.
- The method provides a robust and physically sound solution to the buried atoms problem.
- Demonstrated effectiveness in ZIF-8, IRMOF-1, and ITQ-29 crystal structures.
Conclusions:
- DM-REPEAT represents a significant advancement in calculating partial charges for periodic systems.
- This approach offers a more reliable and accurate method for molecular simulations.
- First-time application of this combined fitting strategy to periodic systems.
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