Study of Atomic Hydrogen in Brazilian Rubellite by EPR Spectroscopy

摘要

Aims: The Electron Paramagnetic Resonance (EPR) absorption study of atomic hydrogen is an useful tool that offers perhaps the first direct experimental method to study the distribution of local ring structures in glasses and in other amorphous materials.Study Design: In the present work we intend to analyze earlier data on the EPR of the atomic hydrogen in Brazilian rubellite crystal. Place and Duration of Study: Institute of Physics, July 2012 to December 2012.Methodology: Isothermal decay behaviors of H0 centers at 353, 364, 373, 383, 393, 403, 413,423, 433 and 443 K, for the EPR absorption line in gamma-irradiated rubellite were analyzed using a kinetic model consisting of H0 confined in a cage formed on one side by the brucite octahedrons and on another side by ions of Y+ (Y=Na, K). The parameters describing these defects were determined with a grid optimization method. The isochronal kinetics is simulated taking in account the heating process and the kinetic equations obtained on the basis of this model were solved using the method of Runge-Kutta.Results: It is shown that the decay process consists of two exponential components, which is consistent with the two independent first order kinetics and the model of creation and annihilation of H0 in cages.Conclusion: Two H0 centers were found with activation energies E1 = (0.55 ± 0.04) eV and E2 = (0.99 ± 0.04) eV.