Muon spin rotation study on the behavior of hydrogen in silicates

2015 Fiscal Year Final Research Report

• Project/Area Number: 25610130
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Solid earth and planetary physics
• Research Institution: High Energy Accelerator Research Organization (2015); The University of Tokyo (2013-2014)
• Principal Investigator: Funamori Nobumasa 大学共同利用機関法人高エネルギー加速器研究機構, 物質構造科学研究所, 教授 (70306851)
• Co-Investigator(Renkei-kenkyūsha): KOJIMA Kenji M. 高エネルギー加速器研究機構, 物質構造科学研究所, 准教授 (60302759)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: ミュオンスピン回転法 / ミュオニウム / 中性水素原子 / ケイ酸塩鉱物 / マントル

Outline of Final Research Achievements

We have conducted muon-spin-rotation experiments on high-pressure mantle minerals to explore the possibility that hydrogen may exist in the form of neutral atom in the Earth’s deep mantle. The positive muon implanted in stishovite, a high-pressure phase of quartz, was found to capture electron to form muonium and exist in small and anisotropic interstitial voids of the structure. This finding may suggest the possible existence of neutral atomic hydrogen and challenge the established dogma that hydrogen exists in the form of a hydroxyl group.

Free Research Field

高圧鉱物物理学