Abstract
The coupling efficiency between an adsorbate and a two-dimensional substrate is probed by real-time monitoring of the ultrafast charge transfer between a Cs atom and an ultrathin silver film of varying thickness adsorbed on a Cu(111) surface. For the first two monolayers of the silver film, a reduction in the resonance lifetime of the cesium hybrid state of approximately 35% is observed. When the silver coverage further increases, the resonance lifetime stays constant at a value close to the value for Cs adsorption on a bulk Ag(111) surface. Both the one-electron resonant and the multielectron inelastic contributions to the adsorbate-substrate charge transfer are theoretically evaluated based on wave-packet propagation and approximation. The results support the experimental findings and allow us to assign the observed dependence of the lifetime change in the multielectron inelastic contribution to the electron transfer rate between the Cs resonance and the very top atomic layers of the substrate.
- Received 30 September 2008
DOI:https://doi.org/10.1103/PhysRevB.78.245410
©2008 American Physical Society