Identification of electronic bonding states of hydrogen on Ni(110)

The electronic structure of hydrogen adsorbed on Ni(110) at 150 K has been studied using angle-resolved photoelectron spectroscopy with monochromatized He Iα radiation. At a saturation coverage of 1.5 monolayers, we observe a general shift of the spectral weight away from the Fermi level to higher binding energies indicating the hybridization of hydrogen levels with metal <i>d</i> states. Along selected Ni 3<i>d</i> bands the intensity shift is obvious whereas other bands remain unchanged. In addition, contrary to previous observations, a hydrogen induced state is visible at a binding energy of roughly 1.2 eV.