Approximating free energy and committor landscapes in standard transition path sampling using virtual interface...

Area of Science:

• Computational Chemistry and Physics
• Statistical Mechanics
• Biophysics

Background:

• Transition path sampling (TPS) is effective for rare event investigation but doesn't directly yield free energy landscapes or kinetics.
• Existing extensions like transition interface sampling (TIS) offer kinetics and thermodynamics but are complex and require prior reaction knowledge.
• A method to directly compute free energy from standard TPS simulations is needed.

Purpose of the Study:

• To develop an approximate method for directly computing free energy landscapes from standard transition path sampling simulations.
• To enable simultaneous access to kinetics and thermodynamics using a single TPS simulation.
• To provide an alternative to more complex methods like transition interface sampling.

Main Methods:

• Introduction of virtual interface exchange transition path sampling (VIE-TPS).
• Utilizes rejected pathways from standard TPS simulations for 'waste recycling'.
• Generates an approximate reweighted path ensemble for analysis.

Main Results:

• The VIE-TPS method provides an immediate view of the free energy landscape from a single TPS simulation.
• Enables committor analysis for kinetic insights.
• Offers a more accessible approach compared to traditional TIS.

Conclusions:

• Virtual interface exchange transition path sampling offers a practical way to extract thermodynamic and kinetic information from standard TPS.
• This method simplifies the analysis of rare transitions and free energy landscapes.
• It enhances the utility of standard transition path sampling simulations.