Direct view of the structure of a silica glass fracture surface

The fracture minor surface of a silica glass, prepared at 1 x 10(-11) mbar in the chamber of an ultra-high-vaccum-atomic-force microscope (UHV-AFM), was imaged at 1 x 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 Zachariasen's network structure model of glass. (C) 2001 Elsevier Science B.V. All rights reserved.