CNR-IPCF, Institute of Chemical and Physical Processes , via G. Moruzzi 1 , I-56124 Pisa , Italy.
CNR-ICCOM, Institute of Chemistry of Organometallic Compounds , via G. Moruzzi 1 , I-56124 Pisa , Italy.
J Chem Theory Comput. 2019 Mar 12;15(3):2010-2021. doi: 10.1021/acs.jctc.8b01222. Epub 2019 Feb 20.
The very first stages of nucleation and growth of ZnO nanoparticles in a plasma reactor are studied by means of a multiscale computational paradigm where the DFT-GGA approach is used to evaluate structure and electronic energy of small (ZnO) clusters ( N ≤ 24) that are employed as a training set (TS) for the optimization of a Reactive Force Field (ReaxFF). Reactive Molecular Dynamics (RMD) simulations based on this tuned ReaxFF are carried out to reproduce nucleation and growth in a realistic environment. Inside the reaction chamber the temperature is around 1200 K, and the zinc atoms are oxidized in an oxygen-rich atmosphere at high pressure (about 20 atm), whereas in the quenching chamber where the temperature is lower (about 800 K) the ZnO embryo-nanoclusters are grown. The main processes ruling gas-phase nucleation and growth of ZnO nanoclusters are identified and discussed together with the dependence of the inception time and average stoichiometry of nanoclusters of different size on the composition of precursor material and physical parameters.
采用多尺度计算范例研究了等离子体反应器中 ZnO 纳米粒子成核和生长的最初阶段，其中使用 DFT-GGA 方法来评估用作训练集 (TS) 的小 (ZnO) 簇 (N ≤ 24) 的结构和电子能量，用于优化反应力场 (ReaxFF)。基于此调整后的 ReaxFF 的反应分子动力学 (RMD) 模拟用于在实际环境中再现成核和生长。在反应室内，温度约为 1200 K，锌原子在富氧高压环境中 (约 20 大气压) 被氧化，而在温度较低的淬火室 (约 800 K) 中生长 ZnO 晶种纳米团簇。确定了控制气相 ZnO 纳米团簇成核和生长的主要过程，并与不同尺寸纳米团簇的起始时间和平均化学计量比对前体材料组成和物理参数的依赖性进行了讨论。
