The carbon 1s-to-2π core-to-bound excitation energy and linewidth for CO adsorbed on Pt(111) are reported. A detailed comparison of these absorption data with the core-level photoionization and the electronic decay spectra shows that the optically excited C 1s→2π state decays to a fully screened core-hole state before the core hole decays. The mechanism of this relaxation is discussed. The lifetime contribution to the absorption linewidth for adsorbed CO is found to be equal to or larger than 0.25 eV.

• Received 3 November 1988

DOI:https://doi.org/10.1103/PhysRevB.39.7517