Defects in sodalite-group minerals determined from X-ray-induced luminescence
Date
07/2016Funder
Grant ID
NE/H002715/1
Keywords
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Abstract
The luminescence spectra of a suite of natural sodium framework silicates including four different sodalite variants and tugtupite have been collected during X-ray irradiation as a function of temperature between 20 and 673 K. The origin of the emission bands observed in these samples is attributed to F-centres (360 nm), paramagnetic oxygen defects (400 and 450 nm), S2 − ions (620 nm) and tetrahedral Fe3+ (730 nm). Luminescence in the yellow (550 nm) is tentatively attributed to Mn2+, and red luminescence in Cr-rich pink sodalite is possibly from Cr3+ activation. Sudden reduction in luminescence intensities of emission centres was observed for all minerals in the 60–120 K range. Since it is common to all the sodalite-group minerals, we infer it is a feature of the aluminosilicate framework. Sodalite luminescence has responses from substitutions on the framework (e.g. paramagnetic oxygen defects, Fe3+) which give sodalite properties akin to other framework silicates such as feldspar and quartz. However, the presence of the sodalite cage containing anions (such as F-centres, S2 − ions) imparts additional properties akin to alkali halides. The possibility of coupling between Fe3+ and S2 − is discussed. The overall luminescence behaviour of sodalite group can be understood in terms of competition between these centre types.
Citation
Finch , A A , Mortensen , H F & Maghrabi , M 2016 , ' Defects in sodalite-group minerals determined from X-ray-induced luminescence ' , Physics and Chemistry of Minerals , vol. 43 , no. 7 , pp. 481-491 . https://doi.org/10.1007/s00269-016-0816-7
Publication
Physics and Chemistry of Minerals
Status
Peer reviewed
ISSN
0342-1791Type
Journal article
Rights
© The Author(s) 2016. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Description
The refurbishment of the RLTLCL system and the establishment of it as a facility at St. Andrews were funded by NERC Grant NE/H002715/1.Collections
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