세미나 김상규 교수 [KAIST, 화학과] - Nonadiabatic Reaction Dynamics of Polyatomic Molecules: How Does Electronic Excitation Drive Chemical Reactions?
- 작성일
일시: 2026년 10월 8일 (목) 오후 5시
장소: 과학관 B133호
초록 :
Non-valence bound state (NBS) of the anion is ubiquitous in nature and plays the essential role of the doorway into various dynamical behaviors of anionic reactions.1-4 Here, state-specific chemical dynamics of the metastable NBSs (using the picosecond time-resolved pump-probe spectroscopy on the cryogenically-cooled anions using the velocity-map electron imaging technique) has been investigated to unravel nature of the mode-dependent dynamical behavior of the NBS in terms of the autodetachment and/or concomitant nonvalence-to-valence transformation accompanied by anionic fragmentation reactions. Autodetachment and/or the electron transfer from nonvalence to valence orbital are found to be not only mode-specific but also kinematically competitive, promising the quantum mechanical control of the anionic reaction in general. Regarding the nonadiabatic dynamics near the conical intersection,5-8 Herzberg type-I and type-II pre-dissociation pathways have been distinctly separated out in the picosecond time-resolved product state distributions from the photodissociation of thioanisoles. The pseudo-conical intersection extended along the non-planar geometry has also been explored for 2-fluorothioanisole. Additionally, tunneling reactions of a variety of phenols or thiophenols are interrogated to gain deep insights into dynamical shaping of the tunneling barrier along the multi-dimensional seam coordinates. Recent findings on the structural change of the molecule undergoing predissociation (methylamines) in the proximity of the transition-state are also going to be introduced.