Auger-like correlations in the two-photon above threshold ionization of Ar

The two-photon above-threshold 3 p -ionization of argon for the photon energies exceeding the 3 p -ionization threshold is studied using the correlation function technique. Generalized two-photon ionization cross sections were calculated taking into account many-electron correlations. The calculations demonstrate that the two-photon ionization of Ar at the 3 p 4 threshold is almost entirely a collective process. The decisive contribution in the above-threshold two-photon 3 p -ionization at the exciting-photon energies corresponding to the 3 p → ed giant resonance comes from the Auger-like many-electron correlations of e ′ de ″ d  − 3 pef type.