CO adsorption on the c(8 x 2)-Mn/Cu(100) phase

Adsorption of carbon monoxide on the c(8 x 2) phase of Mn/Cu(100) at 100 K was studied by means of UPS, work function change measurements, and LEED. T wo stages of adsorption can be separated. The first type of molecularly ads orbed CO does not change the substrate structure. No adsorbate-induced supe rstructure can be observed, and the work function is increased by 0.9 eV. F urther adsorption beyond a critical exposure leads to a destruction of the ordered Mn film, and the CO-metal interaction as revealed by UPS is changed accompanied by a decrease of the work function by 0.16 eV. It is not possi ble to re-establish the ordered film structure by annealing. No dissociatio n of CO occurs below 200 K. (C) 1999 Elsevier Science B.V. All rights reser ved.