Implementing reactivity in molecular dynamics simulations with harmonic force fields.

Area of Science:

• Chemistry
• Materials Science
• Computational Science

Background:

• Simulating chemical reactions and material failure from atomic to micrometer scales is computationally challenging.
• Existing methods face limitations in computational feasibility, reliability, and cost.

Purpose of the Study:

• To introduce a novel, efficient, and accurate method for reactive molecular dynamics simulations.
• To enable the simulation of bond breaking and forming reactions in various materials.

Main Methods:

• Developed the Reactive INTERFACE Force Field (IFF-R) by replacing non-reactive harmonic bond potentials with reactive, energy-conserving Morse potentials.
• IFF-R is compatible with established force fields (IFF, CHARMM, PCFF, OPLS-AA, AMBER) for organic and inorganic compounds.
• Enabled bond dissociation with three interpretable Morse parameters per bond type and zero energy upon disconnect; included bond formation via template-based methods.

Main Results:

• Demonstrated IFF-R's applicability to bond breaking in molecules, polymer failure, carbon nanostructures, proteins, composite materials, and metals.
• IFF-R maintains the accuracy of non-reactive force fields.
• Achieved a simulation speed approximately 30 times faster than previous reactive simulation methods.

Conclusions:

• IFF-R offers a computationally feasible, reliable, and cost-effective solution for reactive molecular dynamics simulations.
• The method accurately simulates both bond breaking and forming reactions across diverse material systems.
• This advancement significantly enhances the capability to study material properties and failure mechanisms at the molecular level.