Accuracy of classical force fields for polyethylene structures away from equilibrium

KG Frawley and LH Chen and H Tran and NN Thadhani and R Ramprasad, MRS COMMUNICATIONS (2023).

DOI: 10.1557/s43579-023-00503-6

This study compares the performance of four classical force fields (FFs)-OPLS, PCFF, TraPPE-UA, and ReaxFF-with density functional theory (DFT) for modeling polyethylene (PE) configurations under extreme conditions. We evaluate their accuracy in predicting energies, forces, and stresses. Additionally, the FFs are used to generate a pressure- temperature phase diagram to compare PE's melting behavior against experimental observations. The results indicate that PCFF and OPLS exhibit the closest agreement with DFT, while PCFF, TraPPE-UA, and ReaxFF perform equally when compared to experimental data. This research provides valuable insights for complex simulations, such as high- pressure shock compression studies on PE.

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