Simulating morphologies of organic semiconductors by exploiting low-frequency vibrational modes

Area of Science:

• Computational materials science
• Soft matter physics
• Chemical physics

Background:

• Simulating amorphous organic material morphologies is computationally intensive.
• Dynamical evolution at high densities limits accessible timescales for generating independent states.
• Existing methods struggle with large molecular systems like glassy, protein, and polymeric materials.

Purpose of the Study:

• To develop a computationally efficient method for generating atomistic morphologies of large molecular systems.
• To overcome the limitations of simulating high-density amorphous materials.
• To provide an alternative to computationally expensive molecular dynamics simulations.

Main Methods:

• Identification of rigid molecular segments and construction of an elastic network.
• Normal mode analysis to calculate low-frequency eigenmodes.
• Displacement of rigid segments along eigenmodes for fast structural relaxation.
• Generation of independent states for subsequent short molecular dynamics simulations.

Main Results:

• Rapid generation of numerous structurally independent approximations of atomistic morphologies.
• Achieved fast structural relaxation without force-field parameterization.
• Equilibrium structures obtained through short simulations show agreement with traditional methods.
• Successfully applied to glassy, protein, and polymeric systems.

Conclusions:

• The developed method offers a computationally feasible alternative for simulating large amorphous molecular systems.
• Enables rapid generation of diverse, high-density configurations.
• Reduces the need for extensive computational resources and high-performance computing facilities.