The Influence of Silica Glass Matrix on the Spectra of Interstitial Molecules S2

Abstract

The luminescence of interstitial molecules S2 in silica glass upon excitation with synchrotron radiation is investigated at room and liquid-helium temperatures. The additional photoluminescence band with a maximum in the range of 440 nm at 10 K is assigned to the transition B""3Π u → X3Σ g – in the S2 molecule. The spectra obtained are compared with the spectra of S2 molecules in the gas phase and in the solid inert-gas matrix. It is demonstrated that the influence of the glass matrix on the spectra of S2 molecules manifests itself in two effects. First, the spectral lines are broadened as a result of collisions between the molecules and pore walls in the glass. Second, the luminescence from the molecular terms with energies higher than the energy corresponding to the band gap or the work function of the glass is quenched through the transfer of electronic excitations to the glass network. It is indirectly established that S2 molecules in the glass are located in small pores and interstices whose sizes are only 0.15 A larger than the molecular size. This radically limits the possible chemical reactions accompanying the photodestruction of molecules.