Occupied and unoccupied surface states on Na/Cu(110) were investigated by photoemission and inverse photoemission. By measuring surface state positions at the same adsorbate coverage on the reconstructed and the unreconstructed surface it was demonstrated that the surface states contribute to the total energy balance of the Na induced missing row reconstruction. During the onset of the reconstruction an up-shift of the surface states depopulated an initially occupied Cu-Cu bonding surface state and consequently destabilizes the topmost Cu atoms. The surface state wave-functions were qualitatively analyzed in a tight-binding LCAO picture.

Surface States, Local Bonding and Surface Reconstruction - Na on Cu(110). P.Sandl, E.Bertel: Surface Science, 1994, 302[3], L325-30