Photostimulated desorption of Xe from Au(001) surfaces via transient Xe- formation

TL;DR

This study investigates the mechanisms of Xe atom desorption from Au(001) surfaces induced by photon stimulation, revealing thermal and nonthermal processes and proposing transient Xe- formation as a key factor.

Contribution

It demonstrates the occurrence of nonthermal PSD via transient Xe- formation and estimates its lifetime, providing new insights into photon-induced desorption mechanisms.

Findings

Thermal desorption matches theoretical simulations.

Nonthermal desorption occurs at 6.4 eV photon energy.

Transient Xe- formation has an estimated lifetime of ~15 fs.

Abstract

Photo-stimulated desorption (PSD) of Xe atoms from the Au(001) surface in thermal and nonthermal regimes was investigated by the time-of-flight measurement at photon energies of 6.4 and 2.3 eV. Xe was desorbed in a thermal way at high laser fluence, which was in good agreement with theoretical simulations. At a low laser fluence, on the other hand, desorption was induced only at a photon energy of 6.4 eV by a non-thermal one-photon process. We argue that the nonthermal PSD occurs via transient formation of Xe- on Au(001). The lifetime of Xe- is estimated to be ~15 fs with a classical model calculation. Whereas the electron affinity of Xe is negative in the isolated state, it is stabilized by the metal proximity effect.