Ultrafast photoelectron spectroscopy of solution chemistry

2020 Fiscal Year Final Research Report

• Project/Area Number: 15H05753
• Research Category: Grant-in-Aid for Scientific Research (S)
• Allocation Type: Single-year Grants
• Research Field: Physical chemistry
• Research Institution: Kyoto University
• Principal Investigator: Suzuki Toshinori 京都大学, 理学研究科, 教授 (10192618)
• Co-Investigator(Kenkyū-buntansha): 足立 俊輔 京都大学, 理学研究科, 准教授 (90431874) ; 山本 遥一 京都大学, 理学研究科, 助教 (70837319) ; 堀尾 琢哉 京都大学, 理学研究科, 助教 (40443022)
• Project Period (FY): 2015-05-29 – 2020-03-31
• Keywords: 超高速分光 / 光電子分光 / 水溶液 / 溶媒和電子 / 極端紫外 / フェムト秒

Outline of Final Research Achievements

Ultrafast electron dynamics and non-adiabatic chemical reactions in pure liquids and solutions were traced in real time through changes in the kinetic energy and angular distributions of photoelectrons emitted through the liquid surface. For this purpose, we pioneered ultrafast photoemission spectroscopy, especially using extreme ultraviolet ultrashort pulses generated by high-order harmonic generation. We have succeeded in measuring the ground-state electron binding energy and the solvation time of solvated electrons in water, methanol, and ethanol, and tracking the internal conversion of solvated electrons from their excited state to the ground state in real time. We have also extended our research to the studies of photochemical reactions of various organic molecules and ions near the gas-liquid interface. The ultrafast extreme ultraviolet photoelectron spectroscopy was also applied to the fundamental gas-phase reactions such as the electrocyclic ring-opening reactions.

Free Research Field

物理化学

Academic Significance and Societal Importance of the Research Achievements

化学反応に関与する電子運動を観測する超高速光電子分光は、過去に溶液化学の研究には用いられていなかった。本研究では、放射光施設でなければ得られなかった極端紫外光をテーブルトップレーザーで発生し、液体ジェットに照射することで、溶液反応を光励起直後の状態から生成物まで完全に観測することを可能にした。溶液化学・生命科学・界面化学・環境化学などの研究に大きな発展をもたらす新規方法論を確立した。