First-Principles Study on Various Point Defects Formed by Hydrogen and Helium Atoms in Tungsten

Figure 2

The crystal structure of BCC W contains two H atoms or He atoms. The blue balls and red balls stand for W atoms and the H atoms or He atoms, respectively. (a), (b), and (c) show two atoms located in the substitutional site. (d), (e), and (f) show two atoms located in the tetrahedral site, and (g), (h), and (i) show two atoms located in the octahedral site. The numbers in the figure stand for the distances (in Å) between the two foreign atoms.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)