Fluorescence of Ar(2p)-excited argon clusters

Abstract

Fluorescence of argon and argon clusters is investigated in the Ar(2p)-excitation regime (240–310 eV). Fluorescence excitation spectroscopy shows a different evolution as a function of the average neutral cluster size compared with total electron and ion yields as well as partial ion yields of mass-selected cluster ions. These differences are rationalized in terms of various multiple ionization processes occurring in argon clusters. The dispersed fluorescence shows a broad continuum between 165–290 nm which is interpreted as emission of the “third continuum” of argon. The results suggest that the process leading to fluorescence of clusters in the Ar(2p) regime is due to the radiative decay of doubly charged clusters.