Universität zu Köln

Prescher, Clemens, Prakapenka, Vitali B., Stefanski, Johannes, Jahn, Sandro ORCID: 0000-0002-2137-8833, Skinner, Lawrie B. and Wang, Yanbin ORCID: 0000-0001-5716-3183 (2017). Beyond sixfold coordinated Si in SiO2 glass at ultrahigh pressures. Proc. Natl. Acad. Sci. U. S. A., 114 (38). S. 10041 - 10047. WASHINGTON: NATL ACAD SCIENCES. ISSN 0027-8424

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Abstract

We investigated the structure of SiO2 glass up to 172 GPa using high-energy X-ray diffraction. The combination of a multichannel collimator with diamond anvil cells enabled the measurement of structural changes in silica glass with total X-ray diffraction to previously unachievable pressures. We show that SiO2 first undergoes a change in Si-O coordination number from fourfold to sixfold between 15 and 50 GPa, in agreement with previous investigations. Above 50 GPa, the estimated coordination number continuously increases from 6 to 6.8 at 172 GPa. Si-O bond length shows first an increase due to the fourfold to sixfold coordination change and then a smaller linear decrease up to 172 GPa. We reconcile the changes in relation to the oxygen-packing fraction, showing that oxygen packing decreases at ultrahigh pressures to accommodate the higher than sixfold Si-O coordination. These results give experimental insight into the structural changes of silicate glasses as analogue materials for silicate melts at ultrahigh pressures.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Prescher, Clemens UNSPECIFIED UNSPECIFIED UNSPECIFIED Prakapenka, Vitali B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Stefanski, Johannes UNSPECIFIED UNSPECIFIED UNSPECIFIED Jahn, Sandro UNSPECIFIED orcid.org/0000-0002-2137-8833 UNSPECIFIED Skinner, Lawrie B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wang, Yanbin UNSPECIFIED orcid.org/0000-0001-5716-3183 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-217613
DOI:	10.1073/pnas.1708882114
Journal or Publication Title:	Proc. Natl. Acad. Sci. U. S. A.
Volume:	114
Number:	38
Page Range:	S. 10041 - 10047
Date:	2017
Publisher:	NATL ACAD SCIENCES
Place of Publication:	WASHINGTON
ISSN:	0027-8424
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language X-RAY-DIFFRACTION; MOLECULAR-DYNAMICS; SEISMIC EVIDENCE; VITREOUS SILICA; PREDICTION; LIQUID; ATOP; GEO2; MELT Multiple languages Multidisciplinary Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/21761