UNOCCUPIED ELECTRONIC STATES IN AU(100) SURFACES

We present a joint experimental and theoretical work on the empty stat es of Au(100) surfaces. Both the stable 5 x 10 reconstructed and the m etastable defect-stabilized 1 x 1 surfaces have been investigated by m eans of angle-resolved inverse photoemission, and the electronic struc ture has been theoretically determined for the 1 x 1 surface within th e local density approximation. The experimental spectra for the two su rfaces are very similar, showing in both cases bulk derived transition s and a surface feature corresponding to the n = 1 image-potential sta te. In the spectra from the metastable surface, a strong n = 0 surface resonance is also observed. Comparison with theoretical calculations for the 1 x 1 surface gives generally good agreement for the bulk tran sitions, but suggests that surface defects strongly influence surface states localized near the surface layer.