Structural environment of krypton dissolved in vitreous silica

X-ray absorption measurements on Kr dissolved homogeneously in vitreous silica (1.97 wt% Kr) have been carried out at the Kr K-edge at 4.5 K, representing the first direct determination of the sites occupied by a noble gas. The presence of EXAFS oscillations shows that the Kr atoms are surrounded by...

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Bibliographic Details
Published inThe American mineralogist Vol. 84; no. 9; pp. 1461 - 1463
Main Authors Wulf, Reinhard, Calas, George, Ramos, Aline, Büttner, Heinz, Roselieb, Knut, Rosenhauer, Matthias
Format Journal Article
LanguageEnglish
Published Washington Mineralogical Society of America 01.09.1999
Walter de Gruyter GmbH
Subjects
absorption
Gases
Geochemistry
Krypton
Mineralogy
Minerals
noble gases
Silica
volatiles
X-ray data
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Summary:X-ray absorption measurements on Kr dissolved homogeneously in vitreous silica (1.97 wt% Kr) have been carried out at the Kr K-edge at 4.5 K, representing the first direct determination of the sites occupied by a noble gas. The presence of EXAFS oscillations shows that the Kr atoms are surrounded by a well-defined shell of nearest neighbors, identified as oxygen atoms. The mean Kr-O distances are 3.45±0.1 Å, based on a simple model of Gaussian disorder, with a Debye-Waller factor of σ2 = 0.06 Å2. The large Kr-O distance, which is at the upper limit of the size of the holes existing in vitreous silica, together with the existence of well-defined sites suggests a forced, densely packed environment of oxygen around Kr atoms characteristic of clathrasil surroundings.
ISSN:0003-004X
1945-3027
DOI:10.2138/am-1999-0927