ChIMES: A Force Matched Potential with Explicit Three-Body Interactions for Molten Carbon

Area of Science:

• Materials Science
• Computational Physics
• Physical Chemistry

Background:

• Atomistic simulations are crucial for understanding materials under extreme conditions.
• Existing empirical potentials often struggle to accurately capture complex many-body interactions.
• Kohn-Sham density functional theory (DFT) provides high accuracy but is computationally expensive for large scales.

Purpose of the Study:

• To develop a novel, accurate, and efficient force field for atomistic simulations of materials under extreme conditions.
• To improve the description of dynamic and structural properties compared to previous methods.
• To enable simulations to reach experimental time and length scales while maintaining DFT accuracy.

Main Methods:

• Developed a new force field scheme incorporating explicit two- and three-body interactions.
• Generated models using Chebyshev polynomial fitting via force matching to DFT trajectories.
• Applied the method to liquid carbon near the diamond/graphite/liquid triple point and at elevated conditions.

Main Results:

• The new force field accurately describes dynamic and structural properties of liquid carbon.
• Explicit inclusion of three-body interactions significantly improves model performance.
• The model demonstrates transferability to nearby thermodynamic state points.

Conclusions:

• The developed method offers a significant advancement in simulating materials under extreme conditions.
• This approach bridges the gap between DFT accuracy and the time/length scales of experimental relevance.
• The efficient parameter determination allows for broader application in materials research.