We report that hydrogen can induce surface reconstructions by adsorption even on close-packed substrates. New low-energy electron-diffraction analyses for H/Ni(111) and H/Fe(110) show that consideration of reconstruction is essential for a convincing experiment-theory fit as well as for reliable determination of the adsorption site. There are two different types of reconstruction: Hydrogen pulls nickel atoms out of the surface but pushes iron atoms towards the bulk. These findings are mirrored by a different sign of work-function change for both systems and demonstrate the correlation between geometric and electronic structure.

• Received 4 March 1993

DOI:https://doi.org/10.1103/PhysRevB.47.15969