Single- and Three-Photon Ionization of in Presence of Fano Resonances

We report single- and three-photon ionization cross-sections of the $$ molecule in the region of the Hopfield series of doubly excited states. Results are obtained by solving the time-dependent Schrödinger equation in a hybrid basis combining neutral and ionic CI states with a fully numerical basis. Contributions to the spectrum during and after the interaction are obtained using the tSurff and iSurf methods. Calculations at arbitrary molecular orientation and details of the spectral calculation are presented. For single-photon ionization synchrotron data is reproduced. For three-photon ionization we find a pronounced change of resonance line shape when going from single- to three-photon transitions.