An efficient method to reconstruct free energy profiles for diffusive processes in transition interface sampling and...

Area of Science:

• Computational materials science
• Statistical mechanics
• Chemical physics

Background:

• Calculating free energy profiles is crucial for understanding diffusive processes in materials.
• Existing methods like Transition Interface Sampling (TIS) and Forward Flux Sampling (FFS) can be computationally intensive.
• Simulations often require additional complex calculations, increasing the overall workload.

Purpose of the Study:

• To introduce a novel and efficient Reweighted Partial Path (RPP) method.
• To enable the computation of free energy profiles from single TIS or FFS simulations.
• To avoid the need for supplementary computational techniques.

Main Methods:

• The Reweighted Partial Path (RPP) method utilizes a partial path reweighting strategy.
• It leverages the memory loss assumption inherent in diffusive systems.
• The method derives equilibrium distributions from TIS or FFS trajectories along an order parameter.

Main Results:

• The RPP method successfully computes free energy profiles without requiring reverse TIS or umbrella sampling.
• Its application was demonstrated by calculating the nucleation free energy of copper precipitates in an iron-copper alloy.
• The results showcase the method's efficacy in characterizing early-stage precipitation phenomena.

Conclusions:

• The Reweighted Partial Path (RPP) method offers a simplified and efficient approach to free energy calculations in diffusive systems.
• It reduces computational cost by eliminating the need for additional simulation types.
• RPP provides a valuable tool for studying nucleation and other diffusive processes in materials science.