Figure 1. Coordination defects in pressure-quenched a-silica.

(a) Fraction of 4-, 5- and 6-fold Si versus quenching pressure; (b) Configuration of two types of Si atoms (red: 4-fold, green: 5-fold) in the 15 GPa sample, O atoms are omitted for clarity; (c) Si-Si radial distribution function of 4-fold and 5-fold Si atoms in the 0 GPa and 15 GPa sample (represented by the subscript 4 and 5 in g(r), respectively).