π-dbackbonding band dispersion and final-state effects for the (2×1)p2mgphase of CO on Ni(110)

Abstract
Angle-resolved photoemission spectroscopy has been utilized to measure the dispersion and symmetry of the spectral features in the d-band region of Ni induced by the adsorption of CO. Very strong alterations of the d-band emission characteristics are observed when CO is adsorbed on Ni(110) in the (2×1) p2mg ordered phase. The high density and unique symmetry of this overlayer allow an unambiguous identification of the spectral features as the two-dimensional π-d surface bands induced by the chemical bond of CO to Ni, i.e., by the CO 2π–Ni 3d interaction.