Electron paramagnetic resonance spectroscopy of Fe3+ ions in amethyst: thermodynamic potentials and magnetic susceptibility

Sivaramaiah, G.; Lin, Jinru; Pan, Yuanming

doi:10.1007/s00269-010-0391-2

Cited by 48 publications

(34 citation statements)

References 41 publications

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“…5(a) and 5(b) show that log 10 (N) of the E 1 ' center at g = 2.0 for natural and 10 kGy γ-ray-irradiated amethyst correlates linearly with the reciprocal of temperature (1/T). The slope of this correlation yields the activation energy Ea at -0.03 and -0.02 eV, for E 1 ' of natural and 10 kGy γ-ray-irradiated amethyst, which is consistent with those reported for Fe 3+ in amethysts (Sivaramaiah et al, 2011;Sivaramaiah and Pan, 2012). The pre-exponential coefficient (PEC) has been determined to be 56, 54 per second for E 1 ' in natural and 10 kGy γ-ray-irradiated amethyst from In the calculation of activation energy, we observed negative slope from origin programme and therefore the activation energy is negative.…”

Section: G Sivaramaiahsupporting

confidence: 76%

“…The activation energy represents minimum energy required to liberate an electron from E 1 ' in this amethyst (Sivaramaiah, 2011). The activation energy is slightly more in 10 kGy γ-ray-irradiated amethyst (-0.02 eV)) than natural amethyst (-0.03 eV).…”

Section: Discussionmentioning

confidence: 93%

“…Botis et al (2006Botis et al ( , 2008 studied radiation induced defects in drusy quartz minerals which are collected from McArthur river of Athabaska basin of Canada. Sivaramaiah et al (2011) studied the thermal properties of Fe 3+ center in natural amethyst. Sivaramaiah and Pan (2012) studied the thermal properties of Fe 3+ center in γ-ray-irradiated natural amethyst.…”

Section: Introductionmentioning

confidence: 99%

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Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Sivaramaiah¹

2014

Proceedings of the Indian National Science Academy

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The thermal properties such as Gibbs free energy, activation energy, entropy and enthalpy have been evaluated from the absolute number of spins of E 1 ' in gamma-ray-irradiated and as-is amethysts. It is for the first time to calculate the above properties for E 1 ' in amethyst. The Gibbs free energy of E 1 ' increases with the decrease of temperature from 296 K to 90 K. The activation energy and pre-exponential coefficients of E 1 ' have been evaluated from the logarithmic number of spins and the reciprocal of temperature plot. The Curie temperature and Curie constant of E 1 ' have been evaluated from the reciprocal of magnetic susceptibility and temperature plot. The exchange field, exchange integral and exchange interaction energy have been evaluated from the Curie temperature.

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Section: G Sivaramaiahsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Sivaramaiah¹

2014

Proceedings of the Indian National Science Academy

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“…The EPR spectra are essentially featureless, except for the presence of trace and variable amounts of the rhombic Fe 3+ signal at the effective g value of ~4.38 ( Figure 6) [14,15]. …”

Section: Electron Paramegnetic Resonance (Epr)mentioning

confidence: 99%

Trace Element Compositions and Defect Structures of High-Purity Quartz from the Southern Ural Region, Russia

et al. 2017

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Abstract:Quartz samples of different origin from 10 localities in the Southern Ural region, Russia have been investigated to characterize their trace element compositions and defect structures. The analytical combination of cathodoluminescence (CL) microscopy and spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and trace-element analysis by inductively coupled plasma mass spectrometry (ICP-MS) revealed that almost all investigated quartz samples showed very low concentrations of trace elements (cumulative concentrations of <50 ppm with <30 ppm Al and <10 ppm Ti) and low abundances of paramagnetic defects, defining them economically as "high-purity" quartz (HPQ) suitable for high-tech applications. EPR and CL data confirmed the low abundances of substitutional Ti and Fe, and showed Al to be the only significant trace element structurally bound in the investigated quartz samples. CL microscopy revealed a heterogeneous distribution of luminescence centres (i.e., luminescence active trace elements such as Al) as well as features of deformation and recrystallization. It is suggested that healing of defects due to deformation-related recrystallization and reorganization processes of the quartz lattice during retrograde metamorphism resulted in low concentrations of CL activator and other trace elements or vacancies, and thus are the main driving processes for the formation of HPQ deposits in the investigated area.

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“…The EPR measurements for amethyst crystals proved that ferric (Fe 3+ ) ions are present in substituted orthorhombic sites with a g factor of about 4.28 (SivaRamaiah et al 2011) and in interstitial sites, in channels, with a g factor close to 2.0023. Research conducted by Weil (1984Weil ( , 1994 has proven that Fe 3+ ions in amethyst are present in tetrahedral sites and are accompanied by different positive ion compensators (Li, Na, H), with g factors close to 2.00 and different E/D factors.…”

Section: Introductionmentioning

confidence: 99%

The Mössbauer spectra of prasiolite and amethyst crystals from Poland

Czaja¹,

Kądziołka-Gaweł

Konefał

et al. 2016

Phys Chem Minerals

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Electron paramagnetic resonance spectroscopy of Fe3+ ions in amethyst: thermodynamic potentials and magnetic susceptibility

Cited by 48 publications

References 41 publications

Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Trace Element Compositions and Defect Structures of High-Purity Quartz from the Southern Ural Region, Russia

The Mössbauer spectra of prasiolite and amethyst crystals from Poland

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