ISSN 2630-0583 (Print)

ISSN 2630-0656 (Online)

JCST

Journal of Current Science and Technology

http://jcst.rsu.ac.th

Journal of Current Science and Technology. Vol.9 No.2 , July - December 2019.

The change of crystal field of Gd3+ in natural zircon with heat treatment in oxidizing and reducing atmospheres monitored by ESR spectroscopy

Araya Mungchamnankit and Suwimon Nualpralaksana

Abstract

          Color appearance in gemstones occurred as the consequences of several factors such as impurity ions, color center or inclusions within gemstones.  Variety colors of zircon found in nature, but there is no research showing the clear causes of the color appearance.  The main objective of this research is to involving the ESR spectra of the gadolinium ion (Gd3+) impurity ions of in natural zircon crystal to the color of zircon.  The Zeeman interaction of impurity ions effect produces the crystal field and weak hyperfine interaction.  All of the interactions were calculated by a computer program.  In addition, the symmetry of impurity ion site can be seen with the relation between the resonance magnetic field positions and the applied magnetic field directions in the ESR spectra.  The variation in the crystal field parameters of heat-treated zircon at different atmospheres was found related to the change in the color of zircon. 

Keywords: crystal field, ESR spectroscopy, ESR spectra, gadolinium ion, Gd3+, natural zircon

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DOI: 10.14456/jcst.2019.14