ReaxFF molecular dynamics simulations on thermal decomposition of RDX-based CMDB propellants

Adaptive Force Field Parameter Optimization for Expanding Reaction Simulations within Wide-Ranged Temperature

“…Consequently, with a balance of accuracy and efficiency compared to empirical force fields and QM, ReaxFF has been widely applied to simulate combustion and phenolic pyrolysis of large molecular systems. − For instance, pyrolysis simulation of resin systems involves modeling complex chemistry with bond dissociation and recombination to generate various small molecule products . However, ReaxFF fails to capture phenolic intermediates during resin pyrolysis and match the experimentally observed low resin decomposition temperature of 800 K. In fact, most ReaxFF combustion pyrolysis simulations use temperatures around 3000 K, which are significantly higher than industrial and experimental conditions of 500–1500 K. − These elevated temperatures accelerate kinetic rates, resulting in simulated values that exceed experimental ones and hinder intermediate observation . Moreover, elevated temperatures alter mechanistic channels, changing pathways and impairing accurate product prediction.…”

“…1,2 By fitting to quantum mechanics methods using a training set of ab initio data, ReaxFF overcomes the size and cost limitations of calculations to provide reliable predictions of rate constants, activation barriers, and reaction mechanisms for a wide range of systems. 3 Consequently, with a balance of accuracy and efficiency compared to empirical force fields and QM, ReaxFF has been widely applied to simulate combustion and phenolic pyrolysis of large molecular systems. 4−10 For instance, pyrolysis simulation of resin systems involves modeling complex chemistry with bond dissociation and recombination to generate various small molecule products.…”

“…11 However, ReaxFF fails to capture phenolic intermediates during resin pyrolysis and match the experimentally observed low resin decomposition temperature of 800 K. In fact, most ReaxFF combustion pyrolysis simulations use temperatures around 3000 K, which are significantly higher than industrial and experimental conditions of 500−1500 K. 12−17 These elevated temperatures accelerate kinetic rates, resulting in simulated values that exceed experimental ones and hinder intermediate observation. 3 Moreover, elevated temperatures alter mechanistic channels, changing pathways and impairing accurate product prediction. Therefore, extending the applicability of ReaxFF to perform simulations at low temperatures enables high-precision chemical reactions at temperatures consistent with experiments.…”

“…The ability to simulate chemical reactions accurately, especially on a large scale and over extended timeframes, is crucial for advancing our understanding of complex chemical processes, ultimately leading to novel discoveries and innovations. ReaxFF, based on bond order theory, can dynamically simulate chemical bond breaking and formation, enabling more reactive simulations of large systems compared to traditional empirical force fields. , By fitting to quantum mechanics methods using a training set of ab initio data, ReaxFF overcomes the size and cost limitations of calculations to provide reliable predictions of rate constants, activation barriers, and reaction mechanisms for a wide range of systems . Consequently, with a balance of accuracy and efficiency compared to empirical force fields and QM, ReaxFF has been widely applied to simulate combustion and phenolic pyrolysis of large molecular systems. − For instance, pyrolysis simulation of resin systems involves modeling complex chemistry with bond dissociation and recombination to generate various small molecule products .…”