Attosecond time-resolved photoelectron spectroscopy of liquids

Attosecond spectroscopy has offered promising insights into ultrafast dynamics in solid and gas-phase systems, but has not been extended to the liquid phase yet. We report the achievement of this fundamental advance and demonstrate the measurement of attosecond photoionization delays from liquid water. In combination with theory, these delays reveal electron propagation effects through the aqueous environment and dephasing processes. These results are expected to provide new insights into the nature of photoionization and electron transport in liquid water.