LLM-105的ReaxFF参数优化与分子动力学模拟  

ReaxFF Parameter Optimization and Molecular Dynamics Simulation of LLM-105

作　　者：宋亮 张泳 叶婧 陈博聪 侯方超 苏浩龙 蒋俊 周素芹 SONG Liang;ZHANG Yong;YE Jing;CHEN Bo-cong;HOU Fang-chao;SU Hao-long;JIANG Jun;ZHOU Su-qin(Faculty of Chemical Engineering,Huaiyin Institute of Technology,Huaian Jiangsu 223003,China;School of Chemistry and Chemical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]淮阴工学院化学工程学院,江苏淮安223003 [2]南京理工大学化学与化工学院,江苏南京210094

出　　处：《火炸药学报》2025年第2期138-149,I0006,共13页Chinese Journal of Explosives & Propellants

基　　金：国家自然科学基金(No.22408120);中国博士后科学基金面上资助(No.2023M731685)。

摘　　要：针对ReaxFF初始力场描述2,6-二氨基-3,5-二硝基-1-氧化物(LLM-105)的不足,采用了一种基于梯度下降算法JAX-ReaxFF框架策略,对ReaxFF反应力场进行了重新参数化,特别关注不同键和键角的势能面解离变化;在模拟不同温度和分解速率的反应过程中,深入分析了LLM-105的反应机制。结果表明,当温度为1500 K时,分子反应主要聚焦于聚合和脱氢反应;随着温度的逐渐升高,LLM-105的反应模式呈现出了新的变化,当温度不小于2000 K时,除了原有的聚合和脱氢反应外,还观察到了C-NO_(2)键和C-NH_(2)键的断裂现象;值得注意的是,C-NO_(2)键的断裂成为触发这一系列反应的关键因素;随着分子中的C-NO_(2)和C-NH_(2)键开始发生均裂反应,促进了中间产物HON_(2)、NO_(2)和NH_(3)的形成,并经历一系列复杂的相互反应,最终生成了N_(2)、H_(2)O和CO_(2)等稳定产物,表明该力场能够有效模拟在不同温度和加热速率下的化学反应变化。In view of the poor description of 2,6-diamino-3,5-dinitropyrazine-1-oxide(LLM-105)by the ReaxFF initial force field,a JAX-ReaxFF framework strategy based on the gradient descent algorithm was adopted to reparameterize the ReaxFF reactive force field,paying much attention to the dissociation changes of the potential energy surface of different bonds and bond angles.The reaction mechanism of LLM-105 was analyzed in the simulation of reactions at different temperatures and thermal decomposition rates.The results indicate that at 1500 K,the molecular reactions mainly involved polymerization and dehydrogenation.As the temperature gradually increased,the reaction pathways of LLM-105 showed new changes.When the temperature is not less than 2000 K,in addition to the original polymerization and dehydrogenation reactions,the cleavage of C-NO_(2)bonds and C-NH_(2) bonds were also observed.It is worth noting that the C-NO_(2)bond became the key factor in triggering this series of reactions.As the C-NO_(2)and C-NH_(2) bonds in the molecules began to undergo homolytic cleavage,the formation of intermediates HON_(2),NO_(2)and NH_(3) were formed.These intermediates underwent complex interactions and eventually generated stable products such as N_(2),H_(2)O and CO_(2),indicating that the force field can effectively simulate the changes in chemical reactions at different temperatures and heating rates.

关 键 词：量子化学 LLM-105 梯度下降算法 分解机制 分子动力学模拟 ReaxFF力场 

分 类 号：TJ55[兵器科学与技术—军事化学与烟火技术] O641[理学—物理化学]