Molecular Frame Photoionization Time Delays in a Shape Resonance*

Characterizing time delays in molecular photoionization as a function of the photoelectron emission direction relative to the orientation of the molecule provides unprecedented insights into the attosecond dynamics induced by extreme ultraviolet or X-ray one-photon absorption. The scrutiny of this fundamental process, including the role of continuum resonant states, is of crucial interest for the control of chemical reactions on the attosecond time scale. Here we report single-photon ionization experiments and calculations providing photoionization time delays angle-resolved in the molecular frame, obtained as the energy derivative of the phases of the  photoionization amplitudes. For valence ionization of NO across a shape resonance, the observed time delays varying over a few hundreds of attoseconds are modeled using a multichannel Fano formalism which describes the interfering resonant and non-resonant contributions to the dynamics of the ejected electron. Comparing these results with computed e-NO⁺ scattering highlights the connection of photoionization time delays with Wigner scattering time delays.