The adsorption of CO on W(100) at 80 K has been studied by photoelectron spectroscopy at hv=21.22 eV, and the results have been correlated with previous data for room temperature adsorption. Initial adsorption produces a peak in the emission spectrum at -7.6 eV (relative to the Fermi energy), which is characteristic of the virgin state of adsorbed CO, as well as additional structures which have been previously shown to be characteristic of α- and β-CO. Upon heating the sample to 260 K the -7.6-eV level is depleted and apparent conversion to the β state occurs as indicated by an enhancement of the emission near -5.5 eV. Additional data taken with hv=16.85, 26.9, and 40.81 eV are in general agreement with the measurements at 21.22 eV; however, the peak at -7.6 eV for hv=21.22 eV is shifted to lower kinetic energies by several tenths of an electron volt at the other photon energies.
Journal of Vacuum Science and Technology
and Waclawski, B.
UPS Studies of Virgin CO on W(100), Journal of Vacuum Science and Technology
(Accessed June 9, 2023)