纳米铝团簇初始氧化过程分子动力学模拟

Molecular Dynamics Simulation of Initial Oxidation Process of Nano-Aluminum Clusters

为了研究铝团簇在不同氧化剂中氧化特性及机理,采用ReaxFF反应力场分别对Al-O2和Al-H2O系统的初始氧化过程进行了模拟.在Al-O2系统中,环境温度决定初始氧化过程铝团簇周围是否出现单独Al原子,且存在一个温度阈值,当低于温度阈值时不会出现单独Al原子.在Al-H2O系统中,研究了初始水分子数和温度对初始氧化过程的影响.研究结果表明,水分子对铝团簇表面吸附的水分子离解过程具有促进作用.分析了直径为2nm铝团簇与水发生反应的机理,并与Aln（n=3~20）团簇与水分子反应机理进行了比较,发现纳米铝团簇与水分子反应机理在不同初始水分子数和温度下存在明显差异.

The oxidation characteristics and mechanism of aluminum cluster in different oxidizers were studied. ReaxFF force field was used to simulate the initial oxidation process of Al-O2 system and Al-H2O system respectively. Results show that in Al-O2 system, the temperature of environment decides on whether there exists AI atom around aluminum cluster during initial oxidation. Moreover, there exists a temperature threshold value, below that the A1 atom does not exist. For Al-H2O system, the influences of the number of initial water molecules and the temperature were studied. Studies show that water tends to promote the dissociation of water molecules absorbed by aluminum cluster. Reaction mechanism of aluminum cluster（2 nm） and water molecule were also discussed and compared with that of Aln （n=3=20）cluster and water. The results show that there exists evidence difference in the reaction mechanism when the number of initial water molecule and temperature are distinct.