Studies of angle-resolved photoelectron spectra from oriented NiCO: A model for adsorbed CO

Abstract

We present a study of angle-resolved photoelectron spectra from oriented, linear NiCO. We address the question: How well do simple cluster models such as oriented NiCO simulate adsorbate molecules with respect to photoemission? The photoemission cross sections are obtained using Hartree-Fock electronic continuum orbitals. For the bonding 5σ̃ orbital, we find oriented NiCO to be a better model than oriented CO. The large magnitude of the 5σ̃ photoionization cross sections relative to the 4σ̃ cross section cannot, however, be explained by our calculations without consideration of backscattering of the photoelectrons ejected "downward" into the detector.