Adsorbate-Level Splitting in Hydrogen Chemisorption

Abstract
The electronic energy levels of a hydrogen (1×1) monolayer adsorbed on the (100) tungsten single-crystal face have been investigated by angle-resolved photoemission. Three bands of adsorbate levels are found that disperse and split with angle, at energies of about 2, 6, and 12 eV below the Fermi level. The results suggest that hydrogen chemisorption takes place by interaction with localized directional surface-group orbitals of the tungsten d band.