Analysis of energy level shifts in the photoemission spectra of adsorbed molecules: CO on Ni

Self-consistent Hartree-Fock calculations on a linear NiCO cluster have been used to analyze and interpret the experimental relative binding energy shifts of CO upon adsorption on a Ni surface. Chemical shifts due to the changed environment of the adsorbed molecule are found to contribute significantly to the initial state shifts of nonbonding levels. The final state or relaxation shifts are quite different among groups of levels; bonding, valence non-binding, and core. © 1976.