Influence of shape resonances on the angular dependence of molecular photoionization delays

Abstract

Characterizing time delays in molecular photoionization as a function of the ejected electron emission direction relative to the orientation of the molecule and the light polarization axis provides unprecedented insights into the attosecond dynamics induced by extreme ultraviolet or X-ray one-photon absorption, including the role of electronic correlation and continuum resonant states. Here, we report completely resolved experimental and computational angular dependence of single-photon ionization delays in NO molecules across a shape resonance, relying on synchrotron radiation and time-independent ab initio calculations. The angle-dependent time delay variations of few hundreds of attoseconds, resulting from the interference of the resonant and non-resonant contributions to the dynamics of the ejected electron, are well described using a multichannel Fano model where the time delay of the resonant component is angle-independent. Comparing these results with the same resonance computed in e-NO⁺ scattering highlights the connection of photoionization delays with Wigner scattering time delays.

It is an interesting topic to find the time it takes for an electron to escape an atom or a molecule after photoionization. Here the authors measure the angular dependence of photoionization time delay in the molecular frame and discuss the role of shape resonances.