Effects of water on the reactivity and stability of SiO2 nanostructure.*

To investigate effects of water on the reactivity and stability of SiO2 nanostructure, we have performed first-principles molecular dynamics simulations of SiO2 nano-chain and nano-rod. The SiO2 nanostructures, which have stimulated many current research endeavors, can react with water strongly under internal or external stress. In our study, water monolayer films that cover the entire system are used to study the collective motion of protons. Structure, charge separation, stress dependent bond breaking and formation, and proton conduction are discussed based on results obtained at room temperature. Finally, we extend our effort to carbon nanotubes.