ReaxFF
ReaxFF (for “reactive force field”) is a bond order-based force field developed by Adri van Duin, William A. Goddard, III, and co-workers at the California Institute of Technology. One of its applications is molecular dynamics simulations. Whereas traditional force fields are unable to model chemical reactions because of the requirement of breaking and forming bonds (a force field's functional form depends on having all bonds defined explicitly), ReaxFF eschews explicit bonds in favor of bond orders, which allows for continuous bond formation/breaking. ReaxFF aims to be as general as possible and has been parameterized and tested for hydrocarbon reactions, alkoxysilane gelation, transition-metal-catalyzed nanotube formation, and many advanced material applications such as Li ion batteries, TiO2, polymers, and high-energy materials.[1]
To be able to deal with bond breaking and formation whilst having only 1 single atom type for each element, ReaxFF is a fairly complex force field with many parameters.[2] Therefore an extensive training set is necessary covering the relevant chemical phase space, including bond and angle stretches, activation and reaction energies, equation of state, surface energies, and much more. Usually, but not necessarily, the training data is generated with electronic structure methods. In practice, often DFT calculations are used as a pragmatic approach, especially since more accurate functionals are available. For the parameterization of such a complex force field, global optimization techniques offer the best chance to get a parameter set that most closely describes the training data.[3]
References
- "The ReaxFF reactive force-field: development, applications and future directions", Senftle, T. P. et al., npj Comp. Mat. 2, 15011 (2016) DOI: https://doi.org/10.1038/npjcompumats.2015.11
- "The Force Field File — ReaxFF 2019.3 documentation". Software for Chemistry & Materials. Retrieved 5 February 2020.
- "ReaxFF Parameter Optimization with Monte-Carlo and Evolutionary Algorithms: Guidelines and Insights", G. Shchygol, A. Yakovlev, T. Trnka, A. C. T. van Duin, T. Verstraelen, J. Chem. Theory Comput. 6799-6812 (2019) DOI: 10.1021/acs.jctc.9b00769
- van Duin, Adri C. T.; Dasgupta, Siddharth; Lorant, Francois; Goddard, William A. (2001). "ReaxFF: A Reactive Force Field for Hydrocarbons" (PDF). The Journal of Physical Chemistry A. 105 (41): 9396–9409. Bibcode:2001JPCA..105.9396V. doi:10.1021/jp004368u.
- Nielson, Kevin D.; van Duin, Adri C. T.; Oxgaard, Jonas; Deng, Wei-Qiao; Goddard, William A. (2005). "Development of the ReaxFF Reactive Force Field for Describing Transition Metal Catalyzed Reactions, with Application to the Initial Stages of the Catalytic Formation of Carbon Nanotubes" (PDF). The Journal of Physical Chemistry A. 109 (3): 493–499. Bibcode:2005JPCA..109..493N. doi:10.1021/jp046244d. PMID 16833370.
- Buehler, M.; Van Duin, A.; Goddard, W. A. (2006). "Multiparadigm Modeling of Dynamical Crack Propagation in Silicon Using a Reactive Force Field" (PDF). Physical Review Letters. 96 (9): 095505. Bibcode:2006PhRvL..96i5505B. doi:10.1103/PhysRevLett.96.095505. PMID 16606278.
- Strachan, A.; Kober, E. M.; Van Duin, A. C. T.; Oxgaard, J.; Goddard, W. A. (2005). "Thermal decomposition of RDX from reactive molecular dynamics" (PDF). The Journal of Chemical Physics. 122 (5): 054502. Bibcode:2005JChPh.122e4502S. doi:10.1063/1.1831277.
- Strachan, A.; Van Duin, A. C. T.; Chakraborty, D.; Dasgupta, S.; Goddard, W. A. (2003). "Shock Waves in High-Energy Materials: The Initial Chemical Events in Nitramine RDX" (PDF). Physical Review Letters. 91 (9): 098301. Bibcode:2003PhRvL..91i8301S. doi:10.1103/PhysRevLett.91.098301. PMID 14525217.
- Buehler, M.; Tang, H.; Van Duin, A. C. T.; Goddard, W. A. (2007). "Threshold Crack Speed Controls Dynamical Fracture of Silicon Single Crystals" (PDF). Physical Review Letters. 99 (16): 165502. Bibcode:2007PhRvL..99p5502B. doi:10.1103/PhysRevLett.99.165502. PMID 17995264.
- Ojwang, J. G. O.; Van Santen, R.; Kramer, G. J.; Van Duin, A. C. T.; Goddard, W. A. (2008). "Modeling the sorption dynamics of NaH using a reactive force field" (PDF). The Journal of Chemical Physics. 128 (16): 164714. Bibcode:2008JChPh.128p4714O. doi:10.1063/1.2908737. PMID 18447486.
- Kulkarni, A. D.; Truhlar, D. G.; Goverapet Srinivasan, S.; Van Duin, A. C. T.; Norman, P.; Schwartzentruber, T. E. (2013). "Oxygen Interactions with Silica Surfaces: Coupled Cluster and Density Functional Investigation and the Development of a New ReaxFF Potential". The Journal of Physical Chemistry C. 117: 258. doi:10.1021/jp3086649.
- Deetz, J. D.; Faller, R. (2014). "Parallel Optimization of a Reactive Force Field for Polycondensation of Alkoxysilanes". The Journal of Physical Chemistry B. 118 (37): 10966. doi:10.1021/jp504138r.