Structural and topological changes in silica glass at pressure.

摘要: The effects of high pressures on the structure silica glass have been elucidated using high-energy x-ray diffraction up to 43.5 GPa. A decrease in first two peak positions real-space pair-distribution functions 15 GPa indicates an initial shrinkage tetrahedral units. Above this threshold pressure Si-O bond shape becomes asymmetric and average length coordination number both increase linearly with pressure. Also, strained geometries O-O correlations lead a pronounced topological rearrangement second third nearest neighbors.