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Trust the force, but pull wisely: Structural insights into non-equilibrium response forces from pulling MD
Fabian Koch1, Miriam Jäger2, Victor Tänzel1
1Statistical Physics of Soft Matter and Complex Systems, Institute of Physics, University of Freiburg, 79104 Freiburg, Germany.
The Journal of Chemical Physics
|April 9, 2025
Summary
Researchers developed a new Langevin equation to analyze molecular systems under external driving. The study reveals that the solvent's non-equilibrium response is crucial for accurately interpreting pulling simulation data.
Area of Science:
- * Computational chemistry and biophysics.
- * Statistical mechanics of non-equilibrium systems.
Background:
- * Molecular dynamics simulations are essential for understanding molecular processes.
- * Analyzing systems under external driving requires advanced theoretical frameworks.
Purpose of the Study:
- * To generalize Mori's Langevin equation for driven molecular systems.
- * To investigate the spatial structure of forces in driven systems.
- * To compare non-equilibrium response forces with mean forces in simulations.
Main Methods:
- * Coarse-grained equations of motion analysis.
- * Targeted and steered molecular dynamics simulations.
- * Derivation of a generalized Langevin equation.
Main Results:
- * Developed a generalized Langevin equation with memory kernel, driving force, and non-equilibrium response force.
- * Demonstrated spatial structure in both stationary fluctuating forces and non-equilibrium response forces.
- * Found discrepancies between non-equilibrium response and mean forces for specific pulling protocols.
Conclusions:
- * The non-equilibrium response force is sensitive to driving protocols.
- * Solvent effects in pulling simulations must be carefully considered.
- * The generalized Langevin equation provides a robust framework for driven systems.
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