E′Centers in AmorphousSiO2Revisited: A New Look at an Old Problem

We present theoretical evidence that the paramagnetic $E^{\prime }$ defect centers in amorphous silicon dioxide ( $a-{\mathrm{SiO}}_2$) do not have the same microscopic structures as those well-defined in the corresponding crystalline counterparts such as $\alpha -\mathrm{quartz}$. We then present alternative models of some paramagnetic defects that account for the underlying experimental features of the $E^{\prime }$-center variants in $a-{\mathrm{SiO}}_2$. We suggest that our new model should take the place of the conventional defect model of $a-{\mathrm{SiO}}_2$.