Resonant Auger spectroscopy of argon clusters at the 2p threshold

Resonant Auger spectra of large argon clusters have been measured at the Ar 2p edge. The decay spectra can give some information on the states reached in photon absorption. For example, the observation of the 3p44p final states indicates the occurrence of the 2p3/2->4p excitation in clusters, whereas in atoms this excitation is dipole forbidden. Also the 3p43d final states are identified in the resonant Auger spectra. A peculiar finding is that the normal Auger transitions in bulk cluster atoms are observed below the 2p ionization thresholds. This is explained by the excitation of the 2p electrons into the conduction band, followed by a rapid delocalization of the electron.