Negative ion emission in Coulomb explosion of molecules

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01055
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 14010:Fundamental plasma-related
• Research Institution: Kyoto University
• Principal Investigator: Majima Takuya 京都大学, 工学研究科, 准教授 (50515038)
• Co-Investigator(Kenkyū-buntansha): 寺本 高啓 大阪大学, 放射線科学基盤機構, 特任講師(常勤) (40467056)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: イオンビーム / MeV重イオン / 負イオン / クーロン爆発

Outline of Final Research Achievements

A three-dimensional momentum imaging spectroscopy system was constructed to understand the mechanism of ion emission associated with high-energy heavy ion collisions. Optimal lens conditions for imaging were determined using simple gas molecular targets. A molecular introduction line from a liquid sample was constructed and completed to measure fragment ions from water molecules in the gas phase. Production cross-sections were obtained as a function of the projectile energy. We also performed mass spectrometry on several ion species produced from various polyatomic molecules and found new delayed dissociation channels. In experiments with intense laser pulses, multiphoton ionization experiments were performed with a reflectron-type time-of-flight mass spectrometer.

Free Research Field

原子衝突

Academic Significance and Societal Importance of the Research Achievements

高エネルギー荷電粒子との衝突や光吸収に伴って気相分子から正負の解離イオンが生成される過程は、最も基礎的な分子反応素過程のひとつとして、これまで多くの研究が積み上げられてきた。プラズマ中の気相反応や放射線化学・生物、大気化学、星間化学などにおける基礎過程として重要なだけでなく、原子・分子の電子状態を調べるための反応としても有効性が高い。本研究は高エネルギー重イオンと多原子分子の衝突系に着目し、同時測定などの高度な計測技術を展開して複雑な過程を明らかにすることにより、長い研究の歴史の中で見落とされていた新奇な過程に光を当てるものである。