The geometric structure of pure SF 6 and mixed Ar/SF 6 clusters investigated by core level photoelectron spectroscopy

Abstract

The S 2 p core level photoelectron spectra of Sulphurhexafluoride clusters have been investigated together with heterogeneous Ar/SF 6 clusters, created by doping Ar host clusters (with a mean size of 3600 atoms) with the molecule. Surface and bulk features are resolved both in the argon 2 p and the sulphur 2 p core level photoelectron spectra. For the latter level such features were only observed in the pure cluster case; a single feature characterizes the S 2 p core level spectra of SF 6 doped argon clusters. From the chemical shifts, investigated with respect to SF 6 doping pressure. It can be concluded that the host clusters get smaller with increasing doping pressures and that the SF 6 molecules predominantly stay below the cluster surface, whereas the Argon core stays intact. We have neither observed features corresponding to SF 6 on the cluster surface, nor features corresponding to molecules deep inside the bulk in any of the spectra from the pick-up experiments.