This paper gives an account of our progress towards performing femtosecond timeresolved
photoelectron diffraction on gas-phase molecules in a pump–probe setup
combining optical lasers and an X-ray free-electron laser. We present results of two
experiments aimed at measuring photoelectron angular distributions of laser-aligned 1-
ethynyl-4-fluorobenzene (C8H5F) and dissociating, laser-aligned 1,4-dibromobenzene
(C6H4Br2) molecules and discuss them in the larger context of photoelectron diffraction
on gas-phase molecules. We also show how the strong nanosecond laser pulse used
for adiabatically laser-aligning the molecules influences the measured electron and ion
spectra and angular distributions, and discuss how this may affect the outcome of
future time-resolved photoelectron diffraction experiments.
