Building maps in collective variable space

Area of Science:

• Computational chemistry
• Statistical mechanics
• Molecular dynamics

Background:

• Enhanced sampling techniques like umbrella sampling and metadynamics are vital for free energy calculations.
• Free energy surfaces provide a coarse-grained view of molecular configurations.
• Collective variables (CVs) simplify complex molecular systems.

Purpose of the Study:

• To introduce and validate a method for mapping auxiliary variables in CV space.
• To demonstrate how auxiliary variable maps can analyze molecular system physics.
• To assess the quality of reduced representations defined by CVs.

Main Methods:

• Mapping auxiliary variables onto collective variable (CV) space.
• Utilizing umbrella sampling and metadynamics for enhanced sampling.
• Applying the approach to alanine dipeptide conformational transitions and CO2 crystal phase transitions.

Main Results:

• Auxiliary variable maps reveal insights into molecular system behavior.
• The method effectively analyzes the degeneracy of collective variables.
• Entropy and enthalpy surfaces were computed in CV space for studied systems.

Conclusions:

• Mapping auxiliary variables in CV space is a powerful tool for analyzing molecular simulations.
• This approach enhances the understanding of both system physics and the validity of chosen CVs.
• The technique is applicable to diverse systems, including conformational and phase transitions.