A Mori-Zwanzig Dissipative Particle Dynamics Approach for Anisotropic Coarse Grained Molecular Dynamics

Area of Science:

• Computational Chemistry
• Molecular Dynamics Simulations
• Soft Matter Physics

Background:

• Coarse-grained (CG) molecular dynamics simulations accelerate atomistic simulations but often fail to preserve system dynamics.
• The Mori-Zwanzig approach addresses this for spherical particles but is computationally intensive.
• Existing CG models struggle with anisotropic systems, limiting their applicability.

Purpose of the Study:

• To develop an advanced coarse-grained model that accurately preserves the dynamics of anisotropic systems.
• To extend the Mori-Zwanzig formalism to account for anisotropic conservative and nonconservative interactions.
• To provide a more accurate CG simulation method for complex molecular systems.

Main Methods:

• Developed an Anisotropic Dissipative Particle Dynamics (ADPD) model, extending the Mori-Zwanzig approach.
• Parametrized the CG force field for ellipsoidal particles using atomistic simulations and a force-matching approach.
• Incorporated anisotropic conservative and dissipative forces using Gay-Berne functional forms.

Main Results:

• The ADPD model accurately reproduces both static and dynamic properties of anisotropic systems.
• Compared to other CG models, ADPD demonstrates superior performance.
• The inclusion of anisotropic nonconservative forces successfully preserves microscopic dynamical details, improving diffusivity predictions.

Conclusions:

• The developed ADPD framework effectively generalizes isotropic Dissipative Particle Dynamics (DPD) for anisotropic systems.
• This approach is highly promising for accurate CG modeling of polymers, macromolecules, and biological systems.
• ADPD offers a computationally efficient yet dynamically accurate method for simulating complex anisotropic materials.