One-dimensional atomistic holes, i.e., a single vacancy chain and its bundl
e penetrating a magnesium oxide film were individually produced by converge
nt electron beam irradiation inside a high-resolution transmission electron
microscope. The width of these imperfections ranged from 0.21 nm to 0.42 n
m and was less than that or. a unit cell of the NaCl structure. The imperfe
ctions were line-type lattice defects.