Elucidation of the unified mechanism of molecular nuclear-spin-conversion with use of rotationally resolved spectroscopy
| Project/Area Number |
20K05424
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 32010:Fundamental physical chemistry-related
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| Research Institution | Japan Atomic Energy Agency |
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Principal Investigator |
Yamakawa Koichiro 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 原子力科学研究所 先端基礎研究センター, 研究副主幹 (60633279)
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| Co-Investigator(Kenkyū-buntansha) |
福谷 克之 東京大学, 生産技術研究所, 教授 (10228900)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2022: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
Fiscal Year 2021: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
Fiscal Year 2020: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
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| Keywords | 核スピン転換 / ラマン分光 / テラヘルツ分光 |
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| Outline of Research at the Start |
ラマン分光法，テラヘルツ-赤外吸収分光法，多光子共鳴イオン化法を用い，分子固体の内部，表面に捕捉したH2, H2O, CH4の単量体及びクラスターの核スピン転換速度を測定し，転換機構を解明する．研究は次の2段階で進める．
① H2, H2O, CH4単量体の核スピン転換を同一環境下で測定し，二・多原子分子の転換機構の統一的解明を目指す．
② 異種2量体H2-H2O, H2-CH4, H2O-CH4の核スピン転換を観測する．2量体中の両分子の転換を同時観測すると共に，分子間振動モードも測定することで，転換機構を解き明かす．
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| Outline of Final Research Achievements |
Molecules including the hydrogen nuclei in the rotationally symmetric positions are classified into nuclear spin isomers, according to the quantum number of their resultant spin. In the present work, we targeted at the fundamental molecules of hydrogen, water, ammonia, and methane, and observed the interconversion between the nuclear spin isomers by using rotationally resolved spectroscopy. We isolated hydrogen in condensed layers of carbon dioxide, and detected weak infrared absorption by polarized hydrogen. The conversion rate was determined from its time development. In addition, we investigated the oxygen-isotope effect on the conversion rate of water molecules, and found the abnormal temperature dependence of the conversion rate of ammonia. Furthermore, we analyzed the time evolution of the infrared spectrum of crystalline methane on the basis of the nuclear spin conversion, and determined the assignments of absorption signals in a combination-tone region.
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| Academic Significance and Societal Importance of the Research Achievements |
核スピン転換の研究は，分子と凝縮系との間の磁気相互作用とエネルギー授受の究明という基礎物理学的観点，水素の効率的な液化貯蔵に代表される産業的観点，そして宇宙における天体の熱履歴の解明という天文学的観点から，重要な意義を持つ．本研究で行った一連の実験によって，水素，水，アンモニア，メタンという基本的な分子の核スピン転換特性が明らかになり，転換メカニズムの理解が大きく進んだ．さらに，核スピン転換の解析がスペクトルを解釈する上でも有用であることが，本研究により示された．
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Report
(4 results)
Research Products
(13 results)
