Paramagnetic resonance of F-type centres in photochromic sodalites

McLaughlan, S. D.; Marshall, David J

doi:10.1016/0375-9601(70)90538-4

Cited by 36 publications

(9 citation statements)

References 4 publications

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“…1). Blue, yellow and strong pink colour centres in sodalite are tentatively attributed to sulphur species (McLaughlan and Marshall 1970;Hassib et al 1977) and pale pink colour in AF-07-35 is attributed to an F-centre (Pizani et al 1985). Samples were examined with a commercial mineralogical UV lamp with 'long' (UV-C) and 'short' wave (UV-B) settings.…”

Section: Methodsmentioning

confidence: 99%

Defects in sodalite-group minerals determined from X-ray-induced luminescence

2016

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of sodalite group can be understood in terms of competition between these centre types. Keywords X-ray excited optical luminescence (XEOL) • Thermoluminescence • Sodalite • Framework silicates • Luminescence 6 (O,S) 24 (SO 4 ,Cl) 1-2 ], lazurite [(Na,Ca) 8 Al 6 Si 6 O 24 (S,SO 4 , Cl) 1-2 ] and tugtupite [Na 8 Be 2 Al 2 Si 2 Si 6 O 24 Cl 2 ]. Some are prized as semi-precious stones (e.g. ultramarine and lapis lazuli) because the sodalite minerals show a range of colours including blue, pink, green, yellow, red and colourless. Synthetic analogues are finding applications as pigments (Schlaich et al. 2000) and efficient visible and infrared phosphors (Schipper et al. 1972; Lezhina et al. 2006). Some natural sodalites are tenebrescent, i.e. they change colour reversibly on exposure to daylight, a property which has inspired potential applications in, for example, security papers and smart coatings for blinds (Armstrong and Weller 2006). Despite being of such importance, there are relatively few published data relating to the luminescence of natural sodalites (e.g.

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Section: Methodsmentioning

confidence: 99%

Defects in sodalite-group minerals determined from X-ray-induced luminescence

2016

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“…This gives rise to a strong exchange coupling between unpaired electrons, which culminates in an antiferromagnetic transition at 48 K. Evidence for this was found in temperature-dependent NMR, EPR, and static susceptibility measurements presented below. We emphasize that unpaired electrons in Na 4 31 centers have predominantly an s character [10], therefore making SES, to the best of our knowledge, the first example of an s-electron antiferromagnet.…”

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confidence: 87%

“…For localized electrons, paramagnetic shifts may be due to isotropic Fermi contact interaction and/or dipole pseudocontact interaction. The dipolar shift in cubic SES vanishes because s-like electrons associated with tetrahedral Na 4 31 centers have only an isotropic g tensor [10]. This leaves the Fermi contact interaction as the only source of the observed shifts [15] whose magnitude is governed by [16] ͑DB͞B͒ contact 2͑A 0 ͞gm B g N ͒x e ͑T ͒ .…”

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confidence: 99%

Evidence for an Antiferromagnetic Transition in a Zeolite-Supported Cubic Lattice ofFCenters

et al. 1998

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Evidence for a bcc lattice of F centers in sodium-electro-sodalite (SES), synthesized by exposing dehydrated sodalite to sodium vapor, is presented. A high electron spin density in SES produces isotropic contact shifts in nuclear magnetic resonance (NMR) spectra of the framework nuclei whose magnitude is a discrete function of local electron density. Strong exchange coupling between unpaired electrons gives rise to an antiferromagnetic phase transition in SES at T N 48 6 2 K, providing the first example of an s-electron antiferromagnet. [S0031-9007(98)

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“…In sodalite itself and most other sodalite-type phases with Cs(T16T26024)A2 stoichiometry, the T1,T2 tetrahedral cations are ordered and the symmetry is reduced to P43n. Na~(A16Ge6024)CI z and Nas(Ga6Si6024)CI 2 have been synthesized in powdered form by McLaughlan & Marshall (1970). Here, I report the synthesis and refinement of Nas(AI6Ge6024)Cl z, Nas(AI6Ge6024)Br z, and Nas(A16Ge6024)I z.…”

Section: Department Of Geology University Of Westernmentioning

confidence: 99%

Structures of sodium alumino-germanate sodalites [Na8(Al6Ge6O24)A2, A = Cl, Br, I]

Fleet¹

1989

Acta Crystallogr C

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Paramagnetic resonance of F-type centres in photochromic sodalites

Cited by 36 publications

References 4 publications

Defects in sodalite-group minerals determined from X-ray-induced luminescence

Defects in sodalite-group minerals determined from X-ray-induced luminescence

Evidence for an Antiferromagnetic Transition in a Zeolite-Supported Cubic Lattice ofFCenters

Structures of sodium alumino-germanate sodalites [Na8(Al6Ge6O24)A2, A = Cl, Br, I]

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