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Quantum mechanical fragment methods based on partitioning atoms or partitioning coordinates.
Bo Wang1, Ke R Yang, Xuefei Xu
1Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota , 207 Pleasant St. SE, Minneapolis, Minnesota 55455-0431, United States.
Accounts of Chemical Research
|May 21, 2014
Summary
New computational methods improve simulations of large chemical systems. Electrostatically embedded fragment approaches and anchor points reactive potentials offer accurate, affordable simulations for complex molecular dynamics and statistical mechanics.
Area of Science:
- Computational Chemistry
- Theoretical Chemistry
- Chemical Physics
Background:
- Accurate representation of reactive potential energy surfaces is crucial for simulating large systems.
- Current methods like direct dynamics fragment methods and analytic potential energy functions have limitations for complex systems.
Purpose of the Study:
- To develop and evaluate efficient and accurate methods for representing reactive potential energy surfaces for large systems.
- To improve the accuracy of fragment-based quantum mechanical methods and explore alternatives to QM/MM.
Main Methods:
- Investigated three electrostatically embedded fragment methods: EE-MB, EE-MB-CE, and EE-MTA.
- Developed methods for treating quantum mechanical fragment boundaries, including charge redistribution and fluorine capping.
- Introduced the anchor points reactive potential method, partitioning in coordinate space for large systems.
Main Results:
- Electrostatic embedding significantly improves the accuracy of fragment methods compared to unembedded approaches.
- Boundary treatment methods enhance the realism and accuracy of QM/MM-like calculations.
- The anchor points reactive potential method enables accurate potential energy surface fitting for large systems.
Conclusions:
- Electrostatically embedded fragment methods and the anchor points reactive potential provide accurate and affordable simulations for large and complex systems.
- These methods extend the capabilities of simulations beyond current QM/MM limitations.
- The coordinate space partitioning approach is key to applying these methods to systems with many degrees of freedom.