Article

Local spectroscopy of image-potential-derived states: from single molecules to monolayers of benzene on Cu(111).

Department of Chemistry, Surface Science Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
Physical Review Letters (impact factor: 7.37). 01/2007; 97(23):236806. pp.236806
Source: PubMed

ABSTRACT Stark-shifted image-potential states were measured with an STM tip for benzene adsorbed on a Cu(111) surface. A single benzene molecule locally shifts the position of the first image state toward the Fermi level by 0.2 eV relative to its position on the clean surface. The energetic position of this molecule-modified state shifts to lower energy with increasing coverage of benzene on the surface. This is attributed to local surface potential changes that are correlated with the lowering of the crystal work function due to adsorption of benzene.

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Keywords

adsorption
 
benzene
 
benzene adsorbed
 
clean surface
 
crystal work function
 
energetic position
 
local surface potential changes
 
lower energy
 
molecule-modified state shifts
 
single benzene molecule
 
Stark-shifted image-potential states