By using ab initio calculations for clusters, a new reaction path was identified between the di-coordinated Si atom defect and the paramagnetic Eγ’ center in amorphous silica. Under ionizing irradiation, the di-coordinated Si atom interacted with a nearby O atom; relaxing into a structure in which the unpaired electron was distributed between 2 threefold-coordinated Si atoms. Transformation into the Eγ’ center was followed by subsequent formation of a puckered configuration.

Ab initio Calculations for the Interconversion of Optically Active Defects in Amorphous Silica. M.M.G.Alemany, J.R.Chelikowsky: Physical Review B, 2006, 73[23], 235211 (5pp)