Unoccupied Surface State on Ag(110) as Revealed by Inverse Photoemission

By use of the new technique of k-resolved inverse photoemission spectroscopy, an unoccupied s-like surface state on Ag(110) has been detected, which lies within the projected 1 gap of the bulk. At the X» point of the surface Brillouin zone, the energy of the surface state is 1.65 eV above the Fermi level EF, and exhibits a band dispersion towards higher energies. The surface-state emission is immediately quenched when the surface is exposed to very small amounts of oxygen or hydrogen. © 1984 The American Physical Society.