| Инд. авторы: | Yuanming P., Nilges M.J., Mashkovtsev R.I. |
| Заглавие: | Radiation-induced defects in quartz: A multifrequency EPR study and DFT modelling of new peroxy radicals |
| Библ. ссылка: | Yuanming P., Nilges M.J., Mashkovtsev R.I. Radiation-induced defects in quartz: A multifrequency EPR study and DFT modelling of new peroxy radicals // Mineralogical Magazine. - 2009. - Vol.73. - Iss. 4. - P.519-535. - ISSN 0026-461X. - EISSN 1471-8022. |
| Внешние системы: | DOI: 10.1180/minmag.2009.073.4.519; SCOPUS: 2-s2.0-70450204850; |
| Реферат: | eng: A natural quartz, annealed first at 800°C and then irradiated with a 3.5 MeV electron beam, has been investigated by single-crystal electron paramagnetic resonance (EPR) spectroscopy at X- and W-band frequencies from 110 K to 298 K. The W-band EPR spectra allow better separation of two previously reported radiation-induced defects (D and E) and improved determinations of their spin Hamiltonian parameters. These defects have similar g tensors with the gmax axes approximately along an O-O pair and gmin axes perpendicular to the short Si-O bonds, but different 27Al hyperfine structures. Centre E is also characterized by a 29Si hyperfine structure (A/gebe = ∼0.4 mT). These spin Hamiltonian parameters, together with results from density functional theory (DFT) calculations, suggest centre E to be a new variant of peroxy radicals in quartz, whereas a peroxy radical model for centre D remains tentative. Thermal stabilities and decay kinetics of centres D and E have been investigated by use of isochronal and isothermal annealing experiments on a neutron-irradiated quartz and six smoky quartz crystals indruses from a U deposit. © 2009 The Mineralogical Society.
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| Ключевые слова: | Radiation-induced defects; Decay kinetics; Density functional theory calculations; Electron paramagnetic resonance spectroscopy; EPR spectra; EPR spectroscopy; G tensors; Hyperfine structure; Irradiated quartz; MeV-Electrons; Multifrequency EPR; Natural quartz; Peroxy radicals; Quartz crystal; Radiation induced defects; Spin Hamiltonian parameters; Thermal stability; W-band frequencies; Auger electron spectroscopy; simulated annealing; radical; quartz; quantum mechanics; parameterization; numerical model; microstructure; irradiation; electron spin resonance; defect; crystal structure; crystal chemistry; Electron spin resonance spectroscopy; Uranium deposits; Tools; Spin dynamics; Quartz; Quantum theory; Probability density function; Paramagnetism; Paramagnetic resonance; Oxide minerals; Isothermal annealing; EPR spectroscopy; Electron resonance; Electron beams; Density functional theory; Defects; Quartz; Hamiltonians; |
| Издано: | 2009 |
| Физ. характеристика: | с.519-535 |