Atomistic modelling of radiation damage in zircon
Atomistic modelling of radiation damage in zircon
复制标题
锆石辐射损伤的原子模拟
DOI：
10.1088/0953-8984/13/9/317
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
E. Salje
中科院分区：
文献类型：
--
作者：
K. Trachenko;M. Dove;E. Salje
本文报道了用分子动力学方法模拟锆石结构辐射损伤的结果。损伤产生过程的各个阶段，包括弹道和热峰值阶段，被检测、量化和可视化。我们发现，在整个损伤产生过程中，较高的环境温度导致损伤显著降低。我们模拟了位移级联的重叠，发现受损结构抵抗损伤的能力较弱，因为在已经受损的结构中产生了更多的损伤，并且松弛时间增加。计算得到的损伤结构密度在损伤区域核心处呈增大趋势。我们将这种致密化与受损结构中连接的离子多面体链的外观联系起来。连接多面体的数量随着损伤的增加而增加，这与最近的核磁共振结果一致。研究发现，在计算机模拟的时间尺度下，连接锡离子的“聚合物”在退火过程中是基本稳定的，它们的排列可能具有锆石晶体中SiO4四面体排列的“记忆”。
We report the results of simulation of radiation damage in zircon structure using the molecular dynamics technique. The phases of the damage production process, including the ballistic and thermal spike phases, are detected, quantified and visualized. We find that the higher ambient temperature results in substantial decrease of the damage throughout the damage production process. We simulate the overlap of the displacement cascades and find that the damaged structure is less able to resist the damage, in that more damage is produced in the structure that is already damaged and the relaxation time increases. The calculated density of the damaged structure shows the increase in the core of the damaged region. We relate this densification to the appearance of chains of connected SiOn polyhedra in the damaged structure. The number of connected polyhedra increases with the increase of the damage, consistently with recent nuclear magnetic resonance results. `Polymers' of connected SiOn are found to be essentially stable on annealing for the timescales available in computer simulations and their alignment may possess the `memory' of the alignment of SiO4 tetrahedra in crystalline zircon.