Calculation Of Diffusion Barriers For Helium Atom In Vanadium By Effective Medium Theory
有效介质理论计算He原子在金属钒中的扩散行为

The diffusion barriers for the single helium atom in vanadium are studied by effective medium theory, in which the structure relaxation caused by the embedded atom is considered. The most possible diffusion path and diffusion barrier are determined. A single helium atom has the minimum energy about 4.37 eV in the tetrahedral interstitial site of bcc vanadium, and the embedding energy in octahedral interstitial site is larger than that in tetrahedral interstitial site. Helium atom in the bcc vanadium crystal diffuses along the path linked with positions (1, 1/4, 1/2), (1, 1/2, 1/2) and (1, 3/4, 1/2) on the (1 0 0) plane or the equivalent paths on corresponding planes.