Ultrafast Nonadiabatic Dynamics in Gas and Liquid Phases Probed by Extreme-Ultraviolet Time-Resolved Photoelectron Spectroscopy
ORAL
Abstract
Extreme-ultraviolet time-resolved photoelectron spectroscopy (EUV-TRPES) using probe photon energies above 20 eV enables observation of all electronic states involved in nonadiabatic molecular dynamics, without any restriction on spin multiplicity. By combination with liquid-jet techniques, the method is applicable to liquids such as aqueous solutions, allowing direct and critical comparison of reaction dynamics between the gas and liquid phases.
The use of EUV probe pulses has greatly expanded the possibilities for studying liquids, since the inelastic scattering cross section for electron–molecule collisions decreases at higher electron kinetic energies. As a result, the influence of inelastic scattering in the liquid prior to electron emission into vacuum is minimized, yielding an almost unperturbed photoelectron kinetic-energy distribution.
By employing filamentation four-wave mixing and high-order harmonic generation with compressed driving laser pulses, a temporal resolution of 10–14 fs is achieved, enabling the observation of nonadiabatic transitions and vibrational quantum beats. Using the same EUV-TRPES approach, one can directly compare the dynamics of identical molecules—such as nucleobases—in both gas and aqueous phases. The method is also being extended to the study of nonadiabatic dynamics at gas–liquid interfaces, by probing molecules concentrated in the topmost molecular layer.
Suzuki, J. Chem. Phys. 151, 090901 (2019).
Miura et al., J. Am. Chem. Soc. 145, 3369 (2023).
Karashima and Suzuki, J. Am. Chem. Soc. 147, 2291 (2023).
Karashima et al., Opt. Lett. 49, 3777 (2024)
The use of EUV probe pulses has greatly expanded the possibilities for studying liquids, since the inelastic scattering cross section for electron–molecule collisions decreases at higher electron kinetic energies. As a result, the influence of inelastic scattering in the liquid prior to electron emission into vacuum is minimized, yielding an almost unperturbed photoelectron kinetic-energy distribution.
By employing filamentation four-wave mixing and high-order harmonic generation with compressed driving laser pulses, a temporal resolution of 10–14 fs is achieved, enabling the observation of nonadiabatic transitions and vibrational quantum beats. Using the same EUV-TRPES approach, one can directly compare the dynamics of identical molecules—such as nucleobases—in both gas and aqueous phases. The method is also being extended to the study of nonadiabatic dynamics at gas–liquid interfaces, by probing molecules concentrated in the topmost molecular layer.
Suzuki, J. Chem. Phys. 151, 090901 (2019).
Miura et al., J. Am. Chem. Soc. 145, 3369 (2023).
Karashima and Suzuki, J. Am. Chem. Soc. 147, 2291 (2023).
Karashima et al., Opt. Lett. 49, 3777 (2024)
*This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI Grant (21H04970).
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Presenters
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Toshinori Suzuki
- Kyoto Univ