Calculation update! New properties have been added to the website for dislocation monopole core structures, dynamic relaxes of both crystal and liquid phases, and melting temperatures! Currently, the results for these properties predominately focus on EAM-style potentials, but the results will be updated for other potentials as the associated calculations finish. Feel free to give us feedback on the new properties so we can improve their representations as needed.
Warning! Note that elemental potentials taken from alloy descriptions may not work well for the pure species. This is particularly true if the elements were fit for compounds instead of being optimized separately. As with all interatomic potentials, please check to make sure that the performance is adequate for your problem.
Citation: M. Wang, S. Md Pratik, N. Nayir, M.S. Tameh, V. Coropceanu, J. Bredas, J. Pyun, A.C.T. van Duin, and S. Saiev (2025), "Atomic‐Scale Mechanistic Insights into the Ring‐Opening Polymerization of Elemental Sulfur", Angewandte Chemie International Edition64(44). DOI: 10.1002/anie.202511640.
Abstract: A detailed understanding of the composition and polymerization mechanism of elemental sulfur remains a decades long unresolved question for modern chemistry. However, the dynamic nature of molten sulfur significantly complicates its accurate characterization. To overcome this challenge, we performed the first comprehensive molecular dynamics (MD) simulations using a ReaxFF reactive force field specifically parameterized to capture the complex ring-opening polymerization dynamics of elemental sulfur. Rigorous development of the force field parameters, trained against extensive quantum mechanical datasets, was key to enabling these large-scale (>10 000 atoms) reactive MD simulations at polymerization-relevant temperatures. This study provides the first detailed atomic-level description of liquid sulfur, elucidating temperature-dependent molecular composition and offering unprecedented insights into sulfur polymerization mechanisms. These are the first simulations to reveal the formation of remarkably large macrocyclic sulfur rings at the onset of polymerization-a discovery that challenges longstanding mechanistic misconceptions, thus reshaping our understanding of sulfur polymerization. Our findings highlight the power of molecular dynamics in exploring complex polymerization processes, with broad impact in dynamic covalent chemistry and covalent adaptable polymers.
Notes: This force field was developed for modeling liquid sulfur undergoing ring-opening polymerization between 160 and 320 °C. It is intended for investigating the atomic-scale mechanisms of sulfur polymerization and the temperature-dependent molecular composition of liquid sulfur. The force field has been validated against quantum mechanical calculations as well as experimental measurements of liquid sulfur density, radial distribution functions, and temperature-dependent changes in composition.