Angle-resolved photoemission study of the Ag band structure along the ΓΔX line

Angle-resolved photoemission experiments have been carried out on Ag(001) in the photon-energy range from 13 to 105 eV with both s- and s-p-polarised synchrotron radiation. The valence-band structure has been determined along the high-symmetry Delta line. For photon energies smaller than 30 eV the photoemission peaks could be interpreted as results of direct transitions between initial and final energy bands in the relativistic self-consistent band structure calculated by Eckardt, Fritsche and Noffke (1984). For photon energies larger than 30 eV the final band was obtained by extrapolation from the calculated Delta ₆ band to the 2 Gamma X point of a free-electron band with inner potential -5.2 eV. Measured critical points for bands numbered with decreasing energy are: Gamma ₈₊=-4.8 eV, Gamma ₇₊=-5.50 eV and Gamma ₈₊=-5.95 eV, in good agreement, within 0.13 eV, with the theoretical values. A surface resonance is also reported 4.1 eV below the Fermi level at the centre of the surface Brillouin zone Gamma which has the same origin as the surface resonances that have been observed on Cu(001) and Pd(001).