Interstellar Amorphous Ice Ggrain: the Role in Chemical Evolution
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- WATANABE Naoki
- Institute of Low Temperature Science, Hokkaido University
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- KOUCHI Akira
- Institute of Low Temperature Science, Hokkaido University
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- MOURI Orie
- Institute of Low Temperature Science, Hokkaido University
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- NAGAOKA Akihiro
- Institute of Low Temperature Science, Hokkaido University
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- HIDAKA Hiroshi
- Institute of Low Temperature Science, Hokkaido University
Bibliographic Information
- Other Title
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- アモルファス氷宇宙塵:宇宙における化学進化の舞台
- アモルファスヒョウ ウチュウジン ウチュウ ニ オケル カガク シンカ ノ ブタイ
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Abstract
Surface reaction on interstellar ice grains is a key process for the chemical evolution in molecular clouds. We have performed a series of experiments to simulate the chemical evolution of the primordial CO molecule on the ice grains. Photochemical and hydrogen atom reactions of CO-H2O binary ice at 15 K were studied because those are anticipated to be the most dominant chemical processes on the surface of grains. It was found that the photochemical reactions produce CO2 with the highest yield, HCOOH, H2CO, CH3OH, and so on and that even at very low temperatures (much lower than activation energies), addition reactions of hydrogen atoms to CO proceed efficiently due to the tunneling effect and produce H2CO and CH3OH. Branching ratio of the yields in photochemical reactions strongly depends on the structure of ice, while hydrogen atom reactions are very sensitive to both the structure and temperature of ice. Considering the physical and chemical conditions of molecular clouds, the experimental results are consistent with the astronomical observation of ice grains.<br>
Journal
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- Shinku
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Shinku 50 (4), 282-290, 2007
The Vacuum Society of Japan
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Keywords
Details 詳細情報について
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- CRID
- 1390282679043942400
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- NII Article ID
- 130000099466
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- NII Book ID
- AN00119871
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- ISSN
- 18809413
- 05598516
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- NDL BIB ID
- 8816490
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- Text Lang
- ja
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
- KAKEN
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- Abstract License Flag
- Disallowed