Atomistic-Scale Simulations of Realistic, Complex, Reactive Materials—The ReaxFF Method, its Applications and Recent Developments

The ReaxFF method provides a highly transferable simulation method for atomistic scale simulations on chemical reactions at the nanosecond and nanometer scale. It combines concepts of bond-order based potentials with a polarizable charge distribution.<br/>Since its initial development for hydrocarbons in 2001¹, we have found that this concept is transferable to applications to elements all across the periodic table, including all first row elements, metals, ceramics and ionic materials². For all these elements and associated materials we have demonstrated that ReaxFF can accurately reproduce quantum mechanics-based structures, reaction energies and reaction barriers, enabling the method to predict reaction kinetics in complicated, multi-material environments at a relatively modest computational expense. At this moment, over 1000 publications including ReaxFF development of applications have appeared in open literature and the ReaxFF code has been distributed around the world and has been implemented in major open-source and commercial computational chemical software packages.<br/>This presentation will describe the current concepts of the ReaxFF method, the current status of the various ReaxFF codes, including parallel implementations, new force field development algorithms that speed up the ReaxFF parameterization from months to weeks and acceleration methods that allow for microsecond-range predictions. Also, we will present and overview of recent and developing applications to complex materials, with a focus on 2D-material defect chemistry^3-4, metal deposition^5-6 and an expansion of ReaxFF for events in graphitic, metallic and polymer materials that require explicit electrons (e-ReaxFF)⁷.<br/><b>References</b><br/>[1] van Duin, A. C. T., Dasgupta, S., Lorant, F., and Goddard, W. A., 2001. ReaxFF: A reactive force field for hydrocarbons. Journal of Physical Chemistry A 105, 9396-9409.<br/>[2] Senftle, T., Hong, S., Islam, M., Kylasa, S.B., Zheng, Y., Shin, Y.K., Junkermeier, C., Engel-Herbert, R., Janik, M., Aktulga, H.M., Verstraelen, T., Grama, A.Y. and van Duin, A.C.T. (2016) The ReaxFF Reactive Force-field: Development, Applications, and Future Directions. Nature Computational Materials 2, 15011.<br/>[3] Hickey, D.R., Nayir, N., Chubarov, M., Choudhury, T.H., Bachu, S., Miao, L., Wang, Y., Qian, C., Crespi, V.H., Redwing, J.M., van Duin, A.C.T. and Alem, N. (2021) Illuminating invisible grain boundaries in coalesced single-orientation WS2 monolayer films. Nano Letters 21, 6487-6495.<br/>[4] Yilmaz, D., Boebinfer, M., Unocic, R.R. and van Duin, A.C.T. (2022) Understanding Defect Evolution in Chalcogenide Thin Films Under Transmission Electron Microscope Journal of Computational and Theoretical Chemistry in preparation.<br/>[5] Nayir, N., Sengul, M.Y., Costine, A.L., Reinke, P., Rajabpour, S., Bansal, A., Kozhakhmetov, A., Robinson, J., Redwing, J. and van Duin, A.C.T. (2022) Atomic-scale Probing of Defect-assisted Ga intercalation through Graphene using ReaxFF Molecular Dynamics Simulations. Carbon 190, 276-290.<br/>[6] Rajabpour, S., Mao, Q., Nayir, N., Robinson, J. and van Duin, A.C.T. (2021) Development and Applications of ReaxFF Reactive Force Fields for Group-III Gas-Phase Precursors and Surface Reactions with Graphene in MOCVD Synthesis Journal of Physical Chemistry 125, 10747-10758.<br/>[7] Leven, I., Hao, H., Tan, S., Penrod, K.A., Akbarian, D., Hossain, M.J., Evangelisti, B., Islam, M., Koski, J., Moore, S., Aktulga, H.M., van Duin, A.C.T. and Head-Gordon, T. (2021) Recent Advances for Improving the Accuracy, Transferability and E_fficiency of Reactive Force Fields. Journal of Chemical Theory and Computation 17, 3237-3251.