マントル鉱物中の水素の存在状態 –分子動力学法からのアプローチ–  [in Japanese] Energy states of hydrogen in nominally anhydrous mantle minerals –The approach of molecular dynamics (MD) method–  [in Japanese]

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Author(s)

    • 寺田 貴洋 TERADA Takahiro
    • 東北大学大学院理学研究科地学専攻|(現) 株式会社 東芝 Department of Mineralogy, Petrology and Economic Geology, Faculty of Science, Tohoku University|(Present address) Toshiba corporation
    • 秋月 瑞彦 AKIZUKI Mizuhiko
    • 東北大学大学院理学研究科地学専攻 Department of Mineralogy, Petrology and Economic Geology, Faculty of Science, Tohoku University

Abstract

Molecular dynamics (MD) simulation was carried out to obtain positions and energy states of hydrogen in nominally anhydrous mantle minerals. An appropriate OH interatomic potential model (Morse-AT) was determined to reproduce vibrational spectrum and bulk modulus of brucite Mg(OH)<sub>2</sub>. Pressure gradient of OH stretching peak position in brucite is negative, showing increase of hydrogen bonding energy with pressure. This developed Morse-AT model was applied for hydrous forsterite, wadsleyite and ringwoodite Mg<sub>2</sub>SiO<sub>4</sub>. Based on the MD simulations, the small amounts of hydrogen in forsterite forms a Si-OH bond, showing lack of the hydrogen bond. In wadsleyite, the O1-site is partially replaced by OH with M3 site magnesium vacancy. In ringwoodite, hydrogen is present at a vacancy of Mg-site and coordinates SiO_4 tetrahedron oxygen. Decreasing O-O interatomic length with an increasing pressure produces a strong hydrogen bond. Hydrogen in the ringwoodite becomes more stable at higher pressure.

Journal

  • Chikyukagaku

    Chikyukagaku 33(4), 221-233, 1999

    The Geochemical Society of Japan

References:  38

Codes

  • NII Article ID (NAID)
    110008679986
  • NII NACSIS-CAT ID (NCID)
    AN00141280
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    0386-4073
  • NDL Article ID
    4917726
  • NDL Source Classification
    ZM41(科学技術--地球科学)
  • NDL Call No.
    Z15-645
  • Data Source
    CJP  NDL  NII-ELS  J-STAGE 
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