Time domain photoelectron spectroscopy of gas-phase molecules

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K05496
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Atomic/Molecular/Quantum electronics
• Research Institution: The University of Tokyo
• Principal Investigator: Minemoto Shinichirou 東京大学, 大学院理学系研究科(理学部), 助教 (90323493)
• Research Collaborator: Shimada Hiroyuki ; Yagishita Akira ; Mizuno Tomoya ; Majima Takuya ; Tsuru Shota
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 光電子分光 / 自由電子レーザー / 高次高調波発生 / 配列分子 / 時間分解分光

Outline of Final Research Achievements

The present study aims to observe the structural dynamics during ultrafast photochemical reactions by the photoelectron diffraction using the free electron laser (FEL), in the extreme ultraviolet (EUV) regions. I focused on developing the time-resolved photoelectron spectroscopy by synchronizing the optical laser and EUV-FEL pulses.
One example is the sideband spectra of Ar 3p photoelectrons by the optical laser and EUV-FEL pulses, which appear only when the two pulses are temporally overlapped. The observed intensities and the angular distributions of sidebands are reasonably reproduced by theoretical simulations by considering the timing jitter between the two pulses.
Another examples are the photoelectron angular distributions of CO2 molecules nonadiabatically aligned by optical laser pulses. The observed alignment dependence of the angular distributions is well reproduced by theoretical simulations, which ensures the validity of our time-resolved measurement methodology.

Free Research Field

原子分子物理学

Academic Significance and Societal Importance of the Research Achievements

超短パルスレーザーを用いた超高速に進行する現象のダイナミクス研究によって、化学反応の本質を理解できるため、多くの研究者が興味を持って研究を続けている。特に、化学反応とは、分子の中で原子の位置が変化することを表わす現象であり、構造の変化を観測することが、化学反応の本質に迫る直接的な手段である。光電子回折法はその有力な手段の一つであり、本研究によって光電子回折の実現直前まで迫ることが可能になった。