6533b852fe1ef96bd12aaad8

RESEARCH PRODUCT

Vacuum-ultraviolet absorption of hydrogenated and deuterated silanol groups and interstitial water molecules in amorphousSiO2

subject

description

Vacuum-ultraviolet (VUV) absorption cross sections of hydrogenated and deuterated silanol groups (SiOX, where $\mathrm{X}=\mathrm{H}$ or D) as well as interstitial water molecules $({\mathrm{X}}_{2}\mathrm{O})$ in amorphous $\mathrm{Si}{\mathrm{O}}_{2}$ $(a\text{\ensuremath{-}}\mathrm{Si}{\mathrm{O}}_{2})$ were determined between photon energies of 7 and $8.2\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. The absorption bands for the deuterated species are blueshifted compared to those for the hydrogenated ones by $\ensuremath{\sim}0.1\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}0.2\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ as a result of a decrease in the zero-point energy associated with the OX groups. The VUV absorption of interstitial ${\mathrm{X}}_{2}\mathrm{O}$ below $8\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ is blueshifted with respect to that of ${\mathrm{X}}_{2}\mathrm{O}$ trapped in rare-gas solids due to the contribution of hydrogen bonding, and is $\ensuremath{\sim}1$ to 2 orders of magnitude stronger than that of SiOX groups.