Photoemission study of CO adsorbed on K/Cu(110). Analysis of adsorbate induced structures

Improved adsorption characteristics of a K predosed Cu(110) surface with a coverage corresponding to a point before the work function minimum have been confirmed. Analysis of the CO-induced orbitals in the photoelectron spectra of the CO/K/Cu(110) interface for low coverages of carbon monoxide adsorbed at 118 It has been done. Noticeable changes of the parameters of the orbitals with increasing CO coverage have been registered. Elongation of the C-O bond without dissociation of the molecule has been deduced from the energetic separation of 3.4 eV between the 4 sigma and the 1 pi orbital. A weakening of the CO-interface bond with coverage has been found on the base of decreasing 5 sigma-1 pi separation with increasing 4 sigma/5 sigma intensity ratio. Perpendicular orientation of CO molecules to the plane of the substrate surface has been concluded from analysis of the constant initial state spectra of the 4 sigma and 5 sigma/1 pi orbitals.