Ab initio calculations of H/sup +/ energetics in SiO/sub 2/: Implications for transport

The process of H/sup +/ diffusion in SiO/sub 2/ is studied using first-principles density-functional theory. This is done by examining stable bonding sites, migration pathways, and barrier heights of H/sup +/ in /spl alpha/-quartz. The H/sup +/ is found to bind to the bridging oxygen site in a variety of ways, but always displaying an attraction to neighboring oxygen atoms. This attraction provides a mechanism for understanding the diffusion pathways and barrier heights for this system. The relative stability of H/sup +/ in SiO/sub 2/ is also discussed in the context of transport.