Direct view of the structure of a silica glass fracture surface

The fracture minor surface of a silica glass, prepared at 1×10−11 mbar in the chamber of an ultra-high-vaccum-atomic-force microscope (UHV–AFM), was imaged at 1×10−8 mbar with high spatial resolution. The features directly seen were interatomic distances, e.g., O–O and Si–O, groupings of atoms, e.g., SiO4 tetrahedra and rings of tetrahedra, and network holes. A comparison with a structure calculated by a molecular dynamics simulation gave good coincidence. This direct view of the silica glass surface supports Zachariasenʹs network structure model of glass.