Weperformed time-resolved photoelectron spectroscopy of valence orbitals of alignedCO2 molecules
using the femtosecond soft x-ray free-electron laser and the synchronized near-infrared laser. By
properly ordering the individual single-shot ion images, we successfully obtained the photoelectron
angular distributions (PADs) of theCO2 molecules aligned in the laboratory frame (LF). The
simulations using the dipole matrix elements due to the time dependent density functional theory
calculations well reproduce the experimental PADs by considering the axis distributions of the
molecules. The simulations further suggest that, when the degrees of alignment can be increased up to
á cos2 qñ > 0.8, themolecular geometries during photochemical reactions can be extracted fromthe
measured LFPADs once the accurate matrix elements are given by the calculations.
