Zusammenfassung
Thermoluminescence (TL) was combined with X-ray diffractometry and
electron paramagnetic resonance (EPR) to identify charge traps and
recombination centres in natural topaz and to help the understanding of
the process of light emission in this solid. According to the results,
colourless samples presented higher TL intensities than coloured
samples, and they also exhibited the highest OH/F occupation
factors. The thermal treatments were found to change the OH/F
ratios since samples treated at about 400 degreesC present higher TL
response and occupation factors. These results indicate that the OH(-)
group is directly connected to the trapping centres in topaz. The EPR
signal with g approximate to 2.02, due to (AlO(4))(0) centres, increases
with the dose. From the TL and the EPR results, it was possible to
confirm that the (AlO(4))(0) centre is the luminescent centre in topaz.
(C) 2003 Elsevier B.V. All rights reserved.
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