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On the calculation of time correlation functions by potential scaling
Chenyue Xing1, Ioan Andricioaei
1Department of Chemistry and The Program in Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, USA.
The Journal of Chemical Physics
|January 28, 2006
Summary
This study introduces a method to extend molecular dynamics simulations for complex systems with poor ergodicity. The technique allows calculation of time correlation functions at much longer timescales than direct simulations, overcoming simulation limitations.
Area of Science:
- Computational Chemistry
- Statistical Mechanics
- Molecular Dynamics
Background:
- Complex systems often suffer from broken ergodicity in molecular dynamics simulations.
- This limitation restricts the accessible timescales for calculating time correlation functions.
Purpose of the Study:
- To present a general method for calculating time correlation functions from molecular dynamics on scaled potentials.
- To overcome ergodicity issues in complex systems and extend simulation timescales.
Main Methods:
- Utilizing scaled potentials in molecular dynamics simulations.
- Employing an action-reweighting scheme based on stochastic path-integral formalism.
- Analyzing two test cases: a bistable potential model and dipeptide bond-vector relaxation.
Main Results:
- The method enables calculation of time correlation functions at timescales orders of magnitude longer than direct simulations.
- Exact time correlation functions of the original system can be obtained in principle.
- Strengths and limitations of the approach were demonstrated through test cases.
Conclusions:
- The proposed method offers a powerful approach to extend simulation timescales for complex systems.
- It provides a pathway to accurately compute time correlation functions beyond direct simulation limits.
- A procedure for estimating time-dependent standard deviation error was outlined.
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