Hartree-Fock-Slater Model Cluster Calculations. II. Hydrogen Chemisorption on Transition Metal Surfaces

Self-consistent Hartree-Fock-Slater model cluster calculations are carried out in order to investigate the electronic structure of hydrogen chemisorption on transition metal surfaces. Orbital energies and results of Mulliken's population analysis are presented for H·Ni5, H·Ni9, H·Pd9 and H·W9 clusters. The level structures of the clusters are also given by density-of-states (DOS) curves and compared with the experimental UPS and EELS spectra. Hydrogen chemisorption gives rise to bonding levels near the bottom of the valence band and antibonding ones on the top. The energy difference between them in H·Ni9 is in good agreement with that obtained by EELS. It is concluded that not only localized d electrons but also sp electrons play important roles in hydrogen-metal bondings. Details of hydrogen-metal bond formation, electronic charge transfer and their differences with adsorbate metals are also discussed.