SURFACE-STATES, LOCAL BONDING, AND SURFACE RECONSTRUCTION - NA ON CU(110)

Occupied and unoccupied surface states on Na/Cu(110) have been investi gated by photoemission and inverse photoemission. By measuring surface state positions at the same adsorbate coverage on the reconstructed a nd the unreconstructed surface it is demonstrated that the surface sta tes contribute to the total energy balance of the Na induced missing r ow reconstruction. During the onset of the reconstruction an up-shift of the surface states depopulates an initially occupied Cu-Cu bonding surface state and consequently destabilizes the topmost Cu atoms. The surface state wavefunctions are qualitatively analyzed in a thight-bin ding LCAO picture.