First-principles study of helium clustering at initial stage in ThO2

The clustering behavior of helium atoms in thorium dioxide has been investigated by first-principles calculations. The results show that He atoms tend to form a cluster around an octahedral interstitial site（OIS）. As the concentration of He atoms in ThO2 increases, the strain induced by the He atoms...

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Bibliographic Details
Published in:中国物理B：英文版 2017-09, Vol.26 (9), p.371-375
Main Author: 邵宽 韩晗 张伟 王昌英 郭永亮 任翠兰 怀平
Format: Article
Language:English
Subjects:
He原子
SDS
二氧化钍
八面体
氦原子
第一性原理计算
结合能
聚类
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Summary:The clustering behavior of helium atoms in thorium dioxide has been investigated by first-principles calculations. The results show that He atoms tend to form a cluster around an octahedral interstitial site（OIS）. As the concentration of He atoms in ThO2 increases, the strain induced by the He atoms increases and the octahedral interstitial site is not large enough to accommodate a large cluster, such as a He hexamer. We considered three different Schottky defect（SD） configurations（SD1, SD2, and SD3）. When He atoms are located in the SD sites, the strain induced by the He atoms is released and the incorporation and binding energies decrease. The He trimer is the most stable cluster in SD1. Large He clusters, such as a He hexamer, are also stable in the SDs.
ISSN:1674-1056
2058-3834
DOI:10.1088/1674-1056/26/9/097101