Figure 4: Photon energy dependence of the calculated cross-sections.
From: Sensitivity of nonlinear photoionization to resonance substructure in collective excitation
Photon energy dependence of the 1-photon (solid black line) and 2-photon (dotted red line) cross-sections calculated with the reduced model (a) and the full model (b). The scales on the left and right axes are chosen such that the maxima of the curves appear at the same height as the 1-photon cross-section peak. The dash–dotted blue lines represent the result for the 2-photon cross-section within the two-step model with one single intermediate resonance state. In the case of the reduced model, this approach captures the main features of the 2-photon cross-section, while for the full model it breaks down. The inset shows the full model 2-photon cross-section with two arrows indicating the energy position of the two underlying resonances calculated within the TDCIS model.
