Runevall O, Sandberg N
Department of Physics, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
J Phys Condens Matter. 2009 Aug 19;21(33):335401. doi: 10.1088/0953-8984/21/33/335401. Epub 2009 Jul 24.
Helium retention and diffusion in molybdenum is studied on an atomistic scale with ab initio methods. The thermal stability of helium-vacancy clusters is quantified within the framework of density functional theory. Calculated helium emission rates are used to derive a desorption spectrum which is compared with experimental results. The agreement between the current calculations and available experiments is satisfactory except in the high temperature end of the spectrum. The current results indicate that above 1100 K He migration is assisted by lattice defects such as vacancies, rather than through interstitial diffusion.
采用从头算方法在原子尺度上研究了氦在钼中的保留和扩散。在密度泛函理论框架内对氦 - 空位团簇的热稳定性进行了量化。利用计算得到的氦发射率得出解吸谱，并与实验结果进行比较。除了解吸谱的高温端外，当前计算结果与现有实验之间的一致性令人满意。当前结果表明，在1100 K以上，氦的迁移是由空位等晶格缺陷辅助的，而不是通过间隙扩散。
