Trapped Electrons in Irradiated Quartz and Silica: II, Electron Spin Resonance

Abstract

The correlation of two paramagnetic defects, observed by the electron spin resonance (ESR) technique, with two optical absorption bands produced by r‐ray or neutron irradiation is indicated. The peaks of the two absorption bards fall at ∼2100 8.u. and 2300 a.u. The effective g values for the ESR lines, for a crystal orientation with respect to the magnetic field of 100.1] parallel to H2, are 2.0006 plusmn; 0.0005 for the 2100 a.u. band, and there are two lines observed for the 2300 a.u. band at [g= 2.0007 and g= 2.00091 ± 0.0005. The correlation of the optical bands and ESR lines was established by a series of bleaching and annealing experiments. These experiments also establish the presence of another center which is not observed directly by either the optical or the ESR technique. ESR lines were observed which were attributed to a hyperfine interaction, A= 7.7 oersteds, of the g= 2.0006 (2100 a.u. band) defect with the Si29 isotope (I = 1/2, 4.7% abundance). Models for these defects, consistent with the experimental data, are suggested.