Adaptive multiscale molecular dynamics of macromolecular fluids

Area of Science:

• Computational Chemistry
• Materials Science
• Molecular Dynamics

Background:

• Adaptive atomistic-coarse-grain (A/CG) simulations are powerful for modeling complex systems.
• Previous A/CG methods faced challenges with the coarse-grained (CG) to atomistic (A) transformation, limiting their applicability.
• The CG → A transformation was particularly problematic for molecules not represented by a single CG particle.

Purpose of the Study:

• To develop a robust and broadly applicable adaptive atomistic-coarse-grain molecular dynamics simulation method.
• To overcome the limitations of on-the-fly CG → A transformations in multiscale simulations.
• To enable accurate simulations of systems with complex molecular representations.

Main Methods:

• Introduced a transitional healing region to manage the CG → A transformation.
• Incorporated rotational dynamics of rigid atomistic fragments within the CG region.
• Implemented error control through analysis of the atomistic-coarse-grain (A ↔ CG) energy flow.

Main Results:

• Successfully demonstrated the adaptive multiscale simulation of liquid hexane.
• Validated the method with simulations of a dilute polymer solution in a theta solvent.
• The new method effectively handles the CG → A transformation for complex molecular structures.

Conclusions:

• The developed A/CG method significantly expands the applicability of adaptive multiscale simulations.
• The combination of a healing region and fragment dynamics provides a robust solution for CG → A transformations.
• This approach offers a reliable tool for studying complex molecular systems with unprecedented accuracy.