Formation and confinement of Wannier excitons in free argon clusters

Abstract

The evolution of Wannier excitons in free argon clusters is investigated using fluorescence excitation spectroscopy with synchrotron-radiation excitation. The energetic positions of the absorption bands are analyzed as a function of the cluster size from their appearance in small clusters up to the solid-state limit in crystallites with a radius R\ensuremath{\approxeq}200 \AA{}. A three- and two-dimensional confinement of bulk and surface states is observed.