Attosecond science is maturing into a transformative tool for measuring and understanding ultrafast electronic and structural dynamics, but its extension to complex systems is hampered by challenges of both technical and fundamental nature. Our group has pioneered attosecond spectroscopy in liquids. Attosecond photoelectron spectroscopy with liquid microjets has been developed and applied to measure delays of 50-70 attoseconds between the photoemission from liquid vs. gas-phase water¹.
