Refining Collective Coordinates and Improving Free Energy Representation in Variational Enhanced Sampling.

Area of Science:

• Computational Chemistry
• Molecular Dynamics
• Biophysics

Background:

• Collective variables are crucial for enhanced sampling efficiency in molecular simulations.
• Identifying optimal collective variables can be a significant challenge.
• Previous work combined time-lagged independent component analysis with metadynamics for improved collective variables.

Purpose of the Study:

• To extend the combination of time-lagged independent component analysis and enhanced sampling to variationally enhanced sampling.
• To develop an efficient scheme leveraging the advantages of variational methods.
• To improve the discovery of collective variables for complex molecular systems.

Main Methods:

• Applied a novel scheme integrating variationally enhanced sampling with time-lagged independent component analysis.
• Utilized an alanine-3 in water system for validation.
• Employed a new basis set for describing dihedral angle arrangements.
• Developed a more accurate method for calculating correlation functions for time-lagged independent component analysis.

Main Results:

• Successfully extracted superior collective variables from a variationally enhanced sampling trajectory.
• Achieved a detailed, low-dimensional representation of the alanine-3 free energy surface.
• Demonstrated the efficiency and advantages of the new variational scheme.

Conclusions:

• The integrated approach offers an efficient strategy for discovering effective collective variables.
• This method significantly enhances the characterization of molecular free energy landscapes.
• The findings pave the way for more accurate and efficient molecular simulations.