Unoccupied orbitals of C and O on Fe(100)

Inverse photoemission experiments from c(2 × 2) carbon and 1 × 1 oxygen overlayers on Fe(100) reveal adsorbate states at 2.5 and 3.9 eV for C and at 1.7 eV for O. They are assigned to antibonding combinations of C 2p and O 2p states with Fe 3d states. For oxygen on Fe(100) the adsorbate state resonates with the minority spin Fe 3d band, but not with the majority band, in agreement with a recent first principles calculation. Together with previous photoemission results we obtain the energy levels for a complete surface reaction, i.e., dissociation/recombination of CO on Fe(100). © 1992.