THE BONDING OF HYDROGEN ON NICKEL STUDIED BY INVERSE PHOTOEMISSION

A k-resolved inverse photoemission study has been carried out on the low temperature phase of the Ni(110)/(1 × 2)H-adsorption system. The H adsorption results in a set of new surface states. Using a simple nearly-free-electron type model the surface state energies can be reproduced by adding an attractive potential on the Ni surface and simultaneously increasing the image plane distance from the surface. A bulk transition into the 4sp band observed on clean Ni(110) is modified by H adsorption indicating the formation of an sp-derived surface resonance. The measured dispersions are also borne out by the model calculation, although it does not take into account the half periodicity of the reconstructed surface. © 1990.