Mixed Resolution Modeling of Interactions in Condensed-Phase Systems

Area of Science:

• Computational chemistry
• Molecular dynamics
• Multiscale modeling

Background:

• Accurate molecular modeling requires balancing computational cost and system detail.
• Existing methods like atomistic or coarse-grained simulations have limitations in scope and accuracy.
• Developing efficient multiscale methods is crucial for simulating complex molecular systems.

Purpose of the Study:

• To introduce and validate a novel mixed resolution interaction (MRI) method for molecular simulations.
• To demonstrate the MRI method's ability to model molecular interactions efficiently.
• To assess the transferability and limitations of MRI models in various chemical environments.

Main Methods:

• Developed a distance-dependent coupling of atomistic and coarse-grained force fields.
• Implemented an "unfolding" scheme for coarse-grained forces at large separations.
• Applied the MRI method to model bulk water, liquid methanol, aqueous solutions, and a phospholipid bilayer.

Main Results:

• MRI models with a sufficiently large atomistic zone (>0.7 nm) accurately simulate bulk water.
• The method effectively models liquid methanol with one- and two-site coarse-graining.
• MRI treatment significantly impacts solute association dynamics in aqueous solutions, necessitating modifications for heterogeneous systems.

Conclusions:

• The MRI method offers a computationally efficient approach to molecular modeling, maintaining atomistic detail.
• Optimizing the atomistic zone and modifying force fields are key for accurate simulations of complex systems.
• The MRI method shows promise for modeling diverse systems, including solvated biomolecular structures.