title: Muonium in stishovite: implications for the possible existence of neutral atomic hydrogen in the earth's deep mantle.
abstract: Hydrogen in the Earth's deep interior has been thought to exist as a hydroxyl group in high-pressure minerals. We present Muon Spin Rotation experiments on SiO2 stishovite, which is an archetypal high-pressure mineral. Positive muon (which can be considered as a light isotope of proton) implanted in stishovite was found to capture electron to form muonium (corresponding to neutral hydrogen). The hyperfine-coupling parameter and the relaxation rate of spin polarization of muonium in stishovite were measured to be very large, suggesting that muonium is squeezed in small and anisotropic interstitial voids without binding to silicon or oxygen. These results imply that hydrogen may also exist in the form of neutral atomic hydrogen in the deep mantle.
authors: Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan.
authors: Nobumasa
authors: N
authors: Funamori
authors: Muon Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan.
authors: Kenji M
authors: KM
authors: Kojima
authors: Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan.
authors: Daisuke
authors: D
authors: Wakabayashi
authors: Department of Earth and Planetary Systems Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
authors: Tomoko
authors: T
authors: Sato
authors: National Institute for Materials Science, Tsukuba 305-0044, Japan.
authors: Takashi
authors: T
authors: Taniguchi
authors: Geodynamics Research Center, Ehime University, Matsuyama 790-8577, Japan.
authors: Norimasa
authors: N
authors: Nishiyama
authors: 1] Geodynamics Research Center, Ehime University, Matsuyama 790-8577, Japan [2] Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550, Japan.
authors: Tetsuo
authors: T
authors: Irifune
authors: Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198, Japan.
authors: Dai
authors: D
authors: Tomono
authors: Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198, Japan.
authors: Teiichiro
authors: T
authors: Matsuzaki
authors: Muon Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan.
authors: Masanori
authors: M
authors: Miyazaki
authors: Muon Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan.
authors: Masatoshi
authors: M
authors: Hiraishi
authors: Muon Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan.
authors: Akihiro
authors: A
authors: Koda
authors: Muon Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan.
authors: Ryosuke
authors: R
authors: Kadono