The effect of network topology on proton trapping in amorphous SiO/sub 2/

We report the results of first-principles quantum chemical calculations of the interactions of H/H/sup +/ with oxide ring structures of varying sizes. The calculations suggest that the binding and stability of protons in amorphous SiO/sub 2/ depend upon the topology of the interacting network. A neutral hydrogen atom, H/sup 0/, does not bind to bridging O atoms in the rings, but may occupy voids within larger rings.