The adsorption, interconversion, and dissociation of CO on Fe(111)

Abstract

Adsorption of CO and the coadsorption of CO with low coverages of K on Fe(111) at temperatures as low as 83 K have been studied with low energy electron diffraction (LEED), thermal desorption spectroscopy (TDS), and high resolution electron energy loss spectroscopy (HREELS). The results indicate that CO fills three different adsorption sites and is mobile enough to access all binding sites after striking the surface at 83 K. A previously unobserved, very low CO stretch vibration is reported at 1325 cm−1 on the unpromoted surface. In addition, a missing metal–CO vibration is reported for an unpromoted surface. The screening mechanism for the missing Fe–CO stretch vibration is discussed in relation to promoted metal surfaces and to other adsorbates which display similar behavior.