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Revisado por pares
The O – (Al 2 ) centre in topaz and its relation to the blue colour
2005; Wiley; Volume: 2; Issue: 1 Linguagem: Inglês
10.1002/pssc.200460192
ISSN1862-6351
AutoresD. N. da Silva, K.J. Guedes, M. V. B. Pinheiro, Stefan Schweizer, J.‐M. Spaeth, Klaus Krambrock,
Tópico(s)Geology and Paleoclimatology Research
Resumophysica status solidi (c)Volume 2, Issue 1 p. 397-400 Original Paper The O–(Al2) centre in topaz and its relation to the blue colour D. N. da Silva, D. N. da Silva Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrazilSearch for more papers by this authorK. J. Guedes, K. J. Guedes Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrazilSearch for more papers by this authorM. V. B. Pinheiro, M. V. B. Pinheiro Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrazilSearch for more papers by this authorS. Schweizer, S. Schweizer Fakultät Naturwissenschaften, Department Physik, Universität Paderborn, Paderborn, GermanySearch for more papers by this authorJ.-M. Spaeth, J.-M. Spaeth Fakultät Naturwissenschaften, Department Physik, Universität Paderborn, Paderborn, GermanySearch for more papers by this authorK. Krambrock, Corresponding Author K. Krambrock klaus@fisica.ufmg.br Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrazilPhone: +55 313499 5625, Fax: +55 31 3499 5600Search for more papers by this author D. N. da Silva, D. N. da Silva Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrazilSearch for more papers by this authorK. J. Guedes, K. J. Guedes Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrazilSearch for more papers by this authorM. V. B. Pinheiro, M. V. B. Pinheiro Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrazilSearch for more papers by this authorS. Schweizer, S. Schweizer Fakultät Naturwissenschaften, Department Physik, Universität Paderborn, Paderborn, GermanySearch for more papers by this authorJ.-M. Spaeth, J.-M. Spaeth Fakultät Naturwissenschaften, Department Physik, Universität Paderborn, Paderborn, GermanySearch for more papers by this authorK. Krambrock, Corresponding Author K. Krambrock klaus@fisica.ufmg.br Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrazilPhone: +55 313499 5625, Fax: +55 31 3499 5600Search for more papers by this author First published: 19 January 2005 https://doi.org/10.1002/pssc.200460192Citations: 11AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Colour-enhanced blue topaz is one of the most traded gemstones. Naturally very rare, mostly topaz is irradiated by neutrons, electrons, gamma radiation and combinations of them. The colour centre is still not identified. It was speculated that it is related to a Si dangling bond defect occupied by two electrons with spin S = 0. We investigated natural blue as well as colourless topaz from different regions in Brazil by electron paramagnetic resonance (EPR), optical absorption and Raman spectroscopy. The results are compared with neutron and gamma-irradiated blue topaz. By EPR two paramagnetic defects are identified in all samples: (i) the peroxy radical (O2–) measured at room temperature and (ii) an (O–) hole centre interacting with two equivalent Al neighbours measured at low temperature. Blue samples show an absorption band centred at 620 nm which is responsible for the blue colour. From our investigation we find that the O–(Al2) hole centre has nearly the same thermal stability as the optical absorption band. However, we cannot say whether it is responsible for the absorption band and the blue colour. We suggest that at least it plays a dominant role in the stabilization of the blue colour. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Citing Literature Volume2, Issue1January 2005Pages 397-400 RelatedInformation
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