Photochemical and photoluminescence studies of O-deficient centers which were stabilized in the bulk, or on the surface, of silica glasses revealed the inhomogeneous nature of their absorption and luminescence spectra. It was concluded that the inhomogeneity of the absorption spectra was due to dispersion of the energy of the S0-S1 transition, whereas the inhomogeneity of the photoluminescence spectra was due to dispersion of the energy barrier to inter-system crossing. It was suggested that the inhomogeneous nature of the O-deficient centers was due to small changes in the geometrical structural parameters of various O-deficient center groups which had very similar chemical properties.

V.N.Bagratashvili, S.I.Tsypina, V.A.Radtsig, A.O.Rybaltovskii, P.V.Chernov, S.S.Alimpiev, Y.O.Simanovskii: Journal of Non-Crystalline Solids, 1995, 180[2-3], 221-