Important parameters of the bulk and surface electronic structure are obtained for Cu(100), Ag(100), Au(100), and ${\mathrm{Cu}}_3$Au(100) surfaces using inverse photoemission with a high-resolution, tunable detector. The transitions from the Fermi level to the upper ${\mathrm{\Delta }}_1$ s,p band are found at 10.5, 9.6, 7.9, and 10.2 eV along the [100] direction, respectively. Their widths are about 1.3 eV. Upper limits for the ${\mathrm{{\rm X}}}_4^{\prime }$ points are found from the intensity cutoff above the band edge at 1.8, 1.9, 2.3, and 1.8 eV, with the best estimates for the ${\mathrm{{\rm X}}}_4^{\prime }$ positions at 1.8, 1.6, 1.6, and 1.8 eV. The n=1 image states are located at 4.1, 3.9, 4.75 (4.85), and 4.5 eV. A possible n=0 surface resonance is seen at 1.4, 1.3, 1.5, and 1.3 eV.

• Received 20 April 1992

DOI:https://doi.org/10.1103/PhysRevB.46.9719