Time-resolved photoelectron spectroscopy of non-adiabatic electronic dynamics in gas and liquid phases

Abstract

Time-resolved photoelectron spectroscopy of non-adiabatic processes in isolated molecules in molecular beams and aqueous solutions at ambient temperatures is discussed. In the former, time–energy mapping of photoelectron kinetic energy and angular distributions is performed with 22 fs time-resolution by photoelectron imaging using a multicolour filamentation light source. The S ₂–S ₁ internal conversion dynamics in pyrazine, benzene and toluene mediated by conical intersections and deactivation of furan from the Rydberg and valence states are discussed. In the latter, a liquid beam photoelectron spectrometer (hemispherical or time-of-flight) is coupled with a sub-MHz non-collinear optical parametric amplifier. Additionally, charge-transfer-to-solvent reactions from I⁻ to polar protic solvents are observed, and the vertical electron binding energies of solvated electrons in bulk solutions are determined.

Keywords:

• ultrafast
• photoelectron spectroscopy
• imaging
• non-adiabatic
• internal conversion
• pyrazine
• benzene
• toluene
• furan
• charge transfer
• solvated electron

Acknowledgements

The author thanks his present and past group members who made great experimental contribution to TRPES: Y. Suzuki, T. Fuji, Y. Tang, T. Horio, H. Kohguchi, Y. Ogi, S.-Y. Liu, H. Shen, K. Sekiguchi and N. Kurahashi. The author also thanks Professors V. Bonacic-Koutechy and R. Mitiric for collaboration on molecular dynamics on the fly and Professor Elliot Bernstein for valuable comments on this article.