石英-α型SiO_2高压相变的分子动力学研究

A NEW PHASE TRANSITION OF QUARTZ-α SiO_2 BY MOLECULAR DYNAMICS SIMULATION

采用在经典离子晶体作用势中附加Morse势 ,并进行必要的量子化修正 ,对石英 α型SiO2 结构随压力变化特性进行分子动力学计算模拟 ,获得了压力高于 2 4 .6GPa ,从晶相向非晶相相变模拟结果 ,并利用其离子间相互作用势、摩尔体积变化、键角等重要信息对模拟结果作了深入的探讨 ,获得了与实验结果较一致的模拟结果。

Pressure-induced amorphization in quartz-α SiO 2 has been investigated using constant-pressure molecular dynamics (MD) calculations with two-body potential. Interatomic potential functions of our new model are composed of Coulomb force, short-range repulsion, van der waals force, and Morse interactions. The calculations were carried out by an improved MD simulation program with a quantum correction (QC). Both the static properties and crystal-to-amorphous phase transition were very well reproduced. Through an analysis of the molar volume, angular correlation functions, we predict new structural transitions for α-quartz SiO 2 when pressure is over 24.6 GPa at room temperature.