Adsorption of Methyl or Methoxy Species on Ni(110)

Abstract

The electronic structure redistribution that occurs when CH3 or CH3O adsorb on the Ni(110) surface is investigated using the extended Huckel tight binding solid state approach. The solid is modeled as a three-atom thickness slab and the adsorbate is viewed as an approaching monolayer. Electron redistribution that occurs on adsorption is analyzed through projected density of state diagrams and changes in population of atomic orbitals of the adsorbate along with changes in electron population of atomic orbitals of surface atoms. Possible tilting of the CH3 or CH3O species on the surface is considered as preliminary steps before a C–H bond is broken. Calculations have been carried out at a coverage of 1/2. Molecular orbitals involved in bonding to Ni(110) are {2a1, 1e, 3a1} for CH3 and {1e, 5a1, 2e} for CH3O. Electron transfer from Ni(110) to the adsorbate depends on the site of adsorption and the geometrical structure and orientation of the adsorbate; for the sites and orientation considered the range of values seen for electron transfer are: CH3 0.674–1.183 e− and CH3O 0.821–0.893 e−.