Pressure-induced Structural Transformations in Framework Crystal Structures

Abstract
Pressure-induced structural transformation of polymorphs of silica (SiO2) at room temperature is studied with the molecular dynamics method. Novel structural transitions are predicted in which the tetrahedral coordination of silicon to oxygen collectively collapses into an octahedral coordination without breaking any Si-O bonds. The relation between such transformations and the atomic diffusion in the liquid phase is briefly discussed.