Raman study of hydrogen-saturated silica glass

Abstract

The Raman spectra of saturated solid solutions of hydrogen and deuterium in silica glass, SiO2-0.6H2 and SiO2-0.63D2, have been measured for the first time at liquid nitrogen temperature. The comparative analysis of H2 phonon modes in solid solution of hydrogen in silica glass and those of hydrogen gas shows a decrease in the frequency of rotational modes contrary to an increase in the H–H stretching vibration mode frequency. Hydrogen rotational modes, overlapped with the phonon modes of silica glass, strengthen at an elevated temperature, while the phonon modes of silica glass soften. The isotopic substitution of hydrogen by deuterium leads to a decrease in the stretching vibration mode frequency proportionally to the square root of D2/H2 mass ratio, whereas rotational mode frequencies decrease as a ratio of D2 to H2 inertia moments. The intensity of H2 phonon modes gradually decreases upon the heating of hydrogen-saturated silica glass along with the evolving of dissolved hydrogen.