Empty surface states, image states, and band edge on Au(111)

Abstract
Inverse-photoemission observations on Au(111) reveal the n=1 image stage, the L1 (L6+) band edge, and the continuation above the Fermi level EF of the well-established Shockley surface state. The image-state binding energy (0.60±0.05 eV) is lower than that obtained on Cu(111) or Ag(111), or that expected on the basis of elementary multiple-reflection theory (0.85 eV). The L1 (L6+) level is found to occur 3.6±0.1 eV above EF. .AE