Electron paramagnetic resonance data on X-irradiated Sn-doped samples which had been produced by using the sol-gel method were presented. Two variants of Sn-related sites were identified. One was an orthorhombic one, with g1 = 1.994, g2 = 1.986 and g3 = 1.975, and an axial one with g|| = 1.994 and g = 1.977. A relationship between the g-anisotropy and the spin-orbit coupling constant among the iso-electronic Si-Ge-Sn series strongly supported the attribution to E'-Sn centers which consisted of unpaired spins in sp3 orbitals of 3-coordinated Sn sites. An asymmetric 215mT doublet, due to hyperfine interaction with Sn isotopes with a non-null nuclear spin, confirmed this attribution.

Identification of Sn Variants of the E Center in Sn-Doped SiO2. N.Chiodini, F.Meinardi, F.Morazzoni, A.Paleari, R.Scotti, G.Spinolo: Physical Review B, 1998, 58[15], 9615-8