为考察反应分子力场ReaxFF对高氯酸铵(AP)推进剂材料模拟的适应性,从文献中选取了两种含C/H/O/N/Cl有机反应力场,对AP系统中含Cl的典型小分子进行结构和能量扫描计算,并对AP高温裂解过程进行了反应分子动力学模拟.通过对比反应力场与量子力学计算结果发现,现有的含Cl有机反应力场在计算HCl以及部分含H、Cl元素的小分子能量时表现较好,但无法合理描述含高价Cl小分子以及含N、O元素小分子的化学键形成和断裂行为.根据力场分子动力学模拟结果的物种分析,现有的反应力场模拟获得了 H2O、O2、NH3、HCl等产物小分子,但未能复现ClO2、HClO4等高价Cl产物以及NO2、N2O的生成,与实验观测有显著差距.
To investigate the adaptability of reactive molecular force field(ReaxFF)on the simulation of ammonium perchlo-rate(AP)propellant materials,two kinds of organic ReaxFF containing C/H/O/N/Cl from the literatures were selected,the structure and energy scanning of typical small molecules containing Cl in the AP system were calculated,and the high-tempera-ture decomposition process of AP using reactive molecular dynamics was simulated.By comparing the results of ReaxFF and quantum mechanics,it is found that the existing organic reaction force field containing Cl performs well in calculating the energy of HCl and some small molecules containing H and Cl elements.However,it cannot describe the chemical bond formation and fracture behavior of small molecules containing high valence Cl,N and O elements.According to the species analysis of force field molecular dynamics simulation results,the existing ReaxFF simulation has obtained small molecules of products such as H2O,O2,NH3,HCl,etc.,but failed to simulate the generation of high valent Cl products such as ClO2 and HClO4,as well as NO2 and N2 O,which is significantly different from experimental observations.