Isothermal annealing of a 620 nm optical absorption band in Brazilian topaz crystals

Isothermal annealing of a 620 nm optical absorption band in Brazilian topaz crystals

Autor Isotani, Sadao Google Scholar
Matsuoka, Masao Google Scholar
Albuquerque, Antonio Roberto Pereira Leite Autor UNIFESP Google Scholar
Instituição Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Resumo Isothermal decay behaviors, observed at 515, 523, 562, and 693 K, for an optical absorption band at 620 nm in gamma-irradiated Brazilian blue topaz were analyzed using a kinetic model consisting of O- bound small polarons adjacent to recombination centers (electron traps). the kinetic equations obtained on the basis of this model were solved using the method of Runge-Kutta and the fit parameters describing these defects were determined with a grid optimization method. Two activation energies of 0.52 +/- 0.08 and 0.88 +/- 0.13 eV, corresponding to two different structural configurations of the O- polarons, explained well the isothermal decay curves using first-order kinetics expected from the kinetic model. On the other hand, thermoluminescence (TL) emission spectra measured at various temperatures showed a single band at 400 nm in the temperature range of 373-553 K in which the 620 nm optical absorption band decreased in intensity. Monochromatic TL glow curve data at 400 nm extracted from the TL emission spectra observed were found to be explained reasonably by using the knowledge obtained from the isothermal decay analysis. This suggests that two different structural configurations of O- polarons are responsible for the 620 nm optical absorption band and that the thermal annealing of the polarons causes the 400 nm TL emission band. (C) 2013 Elsevier B.V. All rights reserved.
Palavra-chave Topaz
Polaron
First order kinetics
Optical absorption
Thermoluminescence
Idioma Inglês
Financiador Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Secretaria de Ciencia e Tecnologia (RHAE)
Financiadora de Estudos e Projetos (FINEP)
Data de publicação 2013-04-15
Publicado em Physica B-condensed Matter. Amsterdam: Elsevier B.V., v. 415, p. 38-43, 2013.
ISSN 0921-4526 (Sherpa/Romeo, fator de impacto)
Publicador Elsevier B.V.
Extensão 38-43
Fonte http://dx.doi.org/10.1016/j.physb.2013.01.040
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000318005300009
Endereço permanente http://repositorio.unifesp.br/handle/11600/36207

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