神经网络势能揭示RDX晶体的热分解机理,Physical Chemistry Chemical Physics

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神经网络势能揭示RDX晶体的热分解机理
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2022-10-05 , DOI: 10.1039/d2cp03511a
Qingzhao Chu ₁ , Xiaoya Chang ₁ , Kang Ma ₂ , Xiaolong Fu ₃ , Dongping Chen ₁

Affiliation

开发了神经网络电位 (NNP) 来研究 1,3,5-三硝基-1,3,5-三嗪 (RDX) 热分解的复杂反应动力学。我们的 NNP 模型被证明具有良好的计算效率并保留了从头算精度，这允许从原子角度研究块状 RDX 晶体的整个分解过程。在 NNP 上进行一系列分子动力学 (MD) 模拟，以计算 RDX 晶体的物理和化学性质。结果表明，NNP可以准确地描述RDX晶体的物理性质，例如晶胞参数和状态方程。RDX热分解的模拟表明，NNP可以从头开始捕捉物种的进化准确性。建立了复杂的反应网络，提供了RDX分解的反应机理。N-N均裂是主要通道，在先前对分离的RDX分子的DFT研究中无法观察到。此外，NO _{2的H 吸收反应被发现是NO 和H}₂ O 形成的关键途径，而HONO 的消除相对较弱。NNP 对 RDX 的复杂反应动力学提供了原子洞察，并且可以扩展到研究新型高能材料的反应机理。

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Revealing the thermal decomposition mechanism of RDX crystals by a neural network potential

A neural network potential (NNP) is developed to investigate the complex reaction dynamics of 1,3,5-trinitro-1,3,5-triazine (RDX) thermal decomposition. Our NNP model is proven to possess good computational efficiency and retain the ab initio accuracy, which allows the investigation of the entire decomposition process of bulk RDX crystals from an atomic perspective. A series of molecular dynamics (MD) simulations are performed on the NNP to calculate the physical and chemical properties of the RDX crystal. The results show that the NNP can accurately describe the physical properties of RDX crystals, such as the cell parameters and the equation of state. The simulations of RDX thermal decomposition reveal that the NNP could capture the evolution of species at ab initio accuracy. The complex reaction network was established, and a reaction mechanism of RDX decomposition was provided. The N–N homolysis is the dominant channel, which cannot be observed in previous DFT studies of isolated RDX molecule. In addition, the H abstraction reaction by NO₂ is found to be the critical pathway for NO and H₂O formation, while the HONO elimination is relatively weak. The NNP gives an atomic insight into the complex reaction dynamics of RDX and can be extended to investigate the reaction mechanism of novel energetic materials.

更新日期：2022-10-05

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