Shock-synthesized glassy and solid silica: intermediates between four- and six-fold coordination

• Published in: High pressure research Vol. 24; no. 4; pp. 471 - 479
• Main Authors: Tschauner, O., Luo, S. N., Asimow, P. D., Ahrens, T. J., Swift, D. C., Tierney, T. E., Paisley, D. L., Chipera, S. J.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.12.2004
• ISSN: 0895-7959; 1477-2299
• DOI: 10.1080/08957950412331331754

Upon compression, many materials undergo major reconstructions of their structure and bonding, including increases in coordination of atoms and changes in bonding character. While transforming, the materials pass through intermediate states, which are often too transient to be captured and examined. Here we discuss the coordination change in silica as an example of a system where such interesting intermediate structural states have been quenched from shock-experiments. On the basis of these results we suggest a relation between the formation of one of these phases and the extension of the liquid-liquid transition boundary into the stability field of solid silica. We report Raman spectra of shock-retrieved vitreous silica which indicate different compression mechanisms for shock-generated amorphous silica and vitreous silica compressed at 300 K. Static recompression of shock-generated glass leads to an amorphous-crystal transition above 13 GPa.