The first direct in situ observations of the production and microsegregation of radiolytic interstitial oxygen resulting from electron beam irradiation of crystal and amorphous oxygen deficient ${\mathrm{SiO}}_2$ polymorphs has been made using cathodoluminescence (CL) microanalysis (spectroscopy and microscopy). Previously unreported near-infrared CL emission is observed at $0.968\pm 0.003\mathrm{eV}$ from crystal $\alpha -{\mathrm{SiO}}_2$ (quartz) and at $0.971\pm 0.003\mathrm{eV}$ from amorphous $a-{\mathrm{SiO}}_2$ (fused quartz and silica glasses) at 290 K. The energy and width of the near-infrared CL emission from electron-irradiated $\alpha -{\mathrm{SiO}}_2$ polymorphs is consistent with the ${\mathrm{O}}_2$ ${}_{}{}^1{}_{}{}^{}\Delta _g^{}{}_{}{}^{}\to {}_{}{}^3{}_{}{}^{}\Sigma _g^{-}{}_{}{}^{}$ transition associated with molecular oxygen.

• Received 29 October 1999

DOI:https://doi.org/10.1103/PhysRevLett.84.3137