摘要
以金属Zr的一种嵌入原子形式(EAM)的势函数为基础,通过引入一个调制函数的办法,在不同范围内修改了EAM势函数的对势部分和原子电子密度分布部分,然后采用分子动力学方法计算点缺陷(间隙原子(SIA)和空位)形成能和初级离位原子(PKA)的阈值能,从而探讨这些物理量对势函数的不同部分的敏感程度。计算结果表明:势函数的对势部分长程范围内的形式对缺陷的形成影响较小,其短程范围的形式对SIA的形成比对空位的形成影响程度更大;对于PKA的阈值能,其敏感区域来自于势函数的对势部分和原子电子密度分布的短程范围部分,但在不同晶向上的PKA的阈值能对势函数的敏感程度有所不同。这些研究结果对于在研究Zr金属的辐照损伤中势函数的选择或构建有指导意义。
For the purpose of detecting the sensitive parts of an embedded atom method（EAM） potential which is considered to be used in molecular dynamics simulation of radiation effects of Zirconium, we introduce a modulation function to modify the pairwise potential and the atomic electron-density distribution of the EAM potential. Based on the modified potential function, the formation energies of the self-interstitial atom （SIA） and the vacancy atom are calculated as well as the displacement threshold energy of primary knock-on atom （PKA）. The results indicate that the short range part of the pairwise potential has more greater influence on the SIAs formation than the vacancy formation. The defect formation energies are also very sensitive to the behavior of the atomic electron-density function in the range which is close to the cutoff distance. The displacement threshold is sensitive to the short range behaviors of both the pairwise potential and the atomic electron-density function, however, the sensitivity is strongly dependent on the crystal-direction.
出处
《原子核物理评论》
CAS
CSCD
北大核心
2013年第4期464-470,共7页
Nuclear Physics Review
基金
国家自然科学基金资助项目(91126001
11175124)~~
关键词
势函数
分子动力学
缺陷形成能
离位阈值
potential function
molecular dynamics
defect formation energy
displacement threshold energy
