Color Centers in Sulfur-Doped Silica Glasses: Spectroscopic Manifestations of an SO2 Interstitial Molecule

The photoluminescence spectra of sulfur-doped silica glass upon excitation into the absorption band at 203 nm and a temperature of 10 K are investigated. It is revealed that the photoluminescence band with a maximum at about 420 nm and the photoluminescence excitation band have a resolved vibrational structure. A model is proposed according to which the bands of absorption at 203 nm and luminescence at 420 nm are assigned to SO^sub 2^ interstitial molecules that are weakly bound to the glass network (the transitions X^sup ~1^ A^sub 1^ [arrow right] C^sup ~1^ B^sub 2^ and a^sup ~3^ B^sub 1^ [arrow right] X^sup ~1^ A^sub 1^, respectively).[PUBLICATION ABSTRACT]