Electron paramagnetic resonance of rhyolite and gamma-irradiated trona minerals

Koksal E., Koseoglu R., Basaran E.

ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES, vol.58, no.5-6, pp.293-298, 2003 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 58 Issue: 5-6
  • Publication Date: 2003
  • Journal Name: ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.293-298
  • Keywords: electron paramagnetic resonance, free radicals, silicate rhyolite, trona, gamma-irradiation, SPIN-RESONANCE, RADICALS, EPR, SPECTRUM, DEFECTS, CALCITE, ESR
  • Ondokuz Mayıs University Affiliated: No

Abstract

Rhyolite from the "Yellow Stone of Nevsehir" and gamma-irradiated trona from the Ankara Mine have been investigated by electron paramagnetic resonance at ambient temperature and at 113 K. Rhyolite was examined by X-ray powder diffraction and found to consist mainly of SiO2. Before gamma-irradiation, the existing paramagnetic species in rhyolite were identified as PO42-, CH2OH, CO3-, SO2-, CO33-, and CO2- free radicals and Fe3+ at ambient temperature. At 113 K SO2-, CO33- and CO2- radicals and Fe3+ were observed. The gamma-irradiation produced neither new species nor detectable effects on these free radicals. The disappearance of some of the radicals at 113 K is attributed to the freezing of their motions. Before gamma-irradiation, the trona mineral shows only Mn2+ lines, but after gamma-irradiation it indicated the inducement of CO33- and CO2- radicals at ambient temperature, 113 K, in addition to the Mn2+ lines. The g and a values of the species were determined.