posted on 2020-02-26, 22:46authored byAdam D. Smith, Tadas Balčiu̅nas, Yi-Ping Chang, Cédric Schmidt, Kristina Zinchenko, Fernanda B. Nunes, Emanuele Rossi, Vít Svoboda, Zhong Yin, Jean-Pierre Wolf, Hans Jakob Wörner
Femtosecond
X-ray absorption spectroscopy (XAS) is a powerful method
to investigate the dynamical behavior of a system after photoabsorption
in real time. So far, the application of this technique has remained
limited to large-scale facilities, such as femtosliced synchrotrons
and free-electron lasers (FEL). In this work, we demonstrate femtosecond
time-resolved soft-X-ray absorption spectroscopy of liquid samples
by combining a sub-micrometer-thin flat liquid jet with a high-harmonic
tabletop source covering the entire water-window range (284–538
eV). Our work represents the first extension of tabletop XAS to the
oxygen edge of a chemical sample in the liquid phase. In the time
domain, our measurements resolve the gradual appearance of absorption
features below the carbon K-edge of ethanol and methanol during strong-field
ionization and trace the valence-shell ionization dynamics of the
liquid alcohols with a temporal resolution of ∼30 fs. This
technique opens unique opportunities to study molecular dynamics of
chemical systems in the liquid phase with elemental, orbital, and
site sensitivity.