无定形态Al2O3结构的分子动力学模拟

采用分子动力学模拟方法研究了无定形态A l2O3的结构,讨论了压力对于体系结构的影响。模拟计算了体系的双体相关函数、最近邻配位数、键长值、以及键角分布,并给出了原子水平的瞬时结构图形。计算结果与已报道的实验结果相符,并比以往的模拟更接近实验事实。模拟的结果还得到了键价理论的验证。模拟的无定形态A l2O3结构主要为(A lO4)5-四面体单元,大多数四面体间由一个连接三个四面体的氧原子连接。这与液态A l2O3短程内的结构是一致的。在模拟的范围内,压力对原子的配位数有一定影响。

Molecular dynamics(MD) simulation for structure of amorphous Al2O3 in different temperatures

The structure properties of the amorphous Al_2O_3 and the impactions of pressure have been investigated by means of the molecular dynamics(MD) technique.The simulation results of the partial pair-distribution functions,the average coordination numbers,the bond-lengths and the bond-angle distributions were compared with the experimental values,and found our MD simulation results are in well agreement with them than the previously simulations.The bond-valence technique provided us a further validation to our simulation results.In the amorphous state there is a short-range order dominated by a somewhat distorted(AlO_4)~(5-) tetrahedron,most of these tetrahedral are connected between them by an oxygen atom which links three tetrahedral to each other.It's similar to the liquid structure.In the studied range,the structures coordination number of the elementary unit increases as the density increases.