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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. [ABSTRACT FROM AUTHOR]

The paper reports on a comparative experimental and theoretical study of circular dichroism in electron angular distribution (CDAD) in the molecular frame (MF) of linear molecules photoionized by circularly or elliptically polarized light. The CDAD is derived from the analysis of the complete molecular frame angular distribution (MFPAD) I(χ,θe,φe), where χ is the orientation of the molecule with respect to the light propagation axis and (θe,φe) the electron emission direction in the MF, using the vector correlation method. The CDAD is quantified by the θe dependence of the left-right emission asymmetry maximum in the plane perpendicular to the light propagation axis k, for a space fixed molecule orthogonal to k. The experimental results for selected valence shell photoionization (PI) reactions in NO, O2, N2O compare very well with the multichannel Schwinger configuration interaction (MCSCI) ab initio calculations. Combined with a simple model of the ionization process, including the partial-wave composition of the initial state and phase shifts estimated from quantum defects for the various scattering partial-waves, these results provide the basis for a general discussion of the circular dichroism effect. This study enables one to disentangle the influence of the (spσ, pπ...) initial valence shell ionized orbital and that of the scattering dynamics on some fingerprint properties of the CDAD. On the other hand, the CDAD for sσ K-shell is purely assigned to a final state scattering effect. This analysis will be extended to PI of non-linear molecules where the circular dichroism characterizes recoil frame photoelectron angular distributions (RFPADs). [ABSTRACT FROM AUTHOR]