Angle-resolved UPS investigation of co-adsorption of CO and K on Fe(110) surface

A symmetry plane for K-CO co-adsorbate at low coverage on Fe(110) surface was found using angle-resolved UPS with polarized light. This plane is parallel to the ⟨110⟩ azimuth of the crystal surface. The dependence of the CO 4σ peak intensity on incidence angle was found to be nearly the same as in the case without K, where the molecular axis of CO is perpendicular to the surface.