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Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...

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Related Experiment Video

Updated: Jun 18, 2026

Flash-and-Freeze: A Novel Technique to Capture Membrane Dynamics with Electron Microscopy

Flash-and-Freeze: A Novel Technique to Capture Membrane Dynamics with Electron Microscopy

Published on: May 1, 2017

Improving fast-switching free energy estimates by dynamical freezing.

Paolo Nicolini¹, Riccardo Chelli

¹Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|November 13, 2009

Summary

This study introduces a novel method to reduce computational costs in free energy calculations using steered molecular dynamics. By dynamically freezing non-essential particles, researchers can achieve accurate results more efficiently.

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Area of Science:

Computational Chemistry
Molecular Dynamics Simulations

Background:

Nonequilibrium pulling simulations often suffer from poor path-ensemble average convergence.
Achieving accurate free energy estimates requires a large number of computationally expensive trajectories.

Purpose of the Study:

To propose a method for improving free energy estimates.
To significantly reduce the computational cost of steered molecular dynamics (SMD) simulations.

Main Methods:

Dynamically freezing particles not directly involved in the driven process.
Synchronously scaling atomic masses and velocities to maintain kinetic energy.
Calculating forces between dynamically frozen particles infrequently.

Main Results:

The proposed method drastically lowers computational cost.
Computational cost becomes independent of the total system size, depending only on the reaction site.
Demonstrated applicability on a model system.

Conclusions:

The developed technique offers a more efficient approach to free energy calculations.
This method enhances the feasibility of complex molecular dynamics simulations.