Resonant Auger spectroscopy of argon clusters at the2pthreshold

Abstract

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 $3{p}^{4}4p$ final states indicates the occurrence of the $2{p}_{3∕2}\ensuremath{\rightarrow}4p$ excitation in clusters, whereas in atoms this excitation is dipole forbidden. Also the $3{p}^{4}3d$ 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.