Publisher Summary Catalytic oxidation of carbon monoxide over catalysts from the platinum group metals has been investigated. Apart from its enormous practical importance, this reaction is considered to proceed through a relatively simple mechanism because only diatomic molecules are involved and product formation occurs presumably only over a very few steps. This chapter discusses the adsorptive properties of the reactants, their mutual interaction, and the mechanism and kinetics of product formation as well as the investigations with well defined single-crystal surfaces. The activity of a catalyst for a particular reaction is strongly dependent on the surface structure. Directive investigation of the influence of the surface structure on the catalytic activity was performed by using a platinum single crystal whose surface was curved in such a way that not only the plane but also vicinals with varying step density of two different crystallographic directions were present.

Elementary Steps in the Catalytic Oxidation of Carbon Monoxide on Platinum Metals

Photoemission studies of adsorbed oxygen and oxide layers

A numerical-variational method for performing self-consistent molecular calculations in the Hartree-Fock-Slater (HFS) model is presented Molecular wavefunctions are expanded in terms of basis sets constructed from numerical HFS solutions of selected one-center atomlike problems Binding energies and wavefunctions for the molecules are generated using a discrete variational method for a given molecular potential In the self-consistent-charge (SCC) approximation to the complete self-consistent-field (SCF) method, results of a Mulliken population analysis of the molecular eigenfunctions are used in each iteration to produce 'atomic' occupation numbers The simplest SCC potential is then obtained from overlapping spherical atomlike charge distributions Molecular ionization energies are calculated using the transition-state procedure; results are given for CO, H2O, H2S, AlCl, InCl, and the Ni5O surface complex Agreement between experimental and theoretical ionization energies for the free-molecule valence levels is generally within 1 eV The simple SCC procedure gives a reasonably good approximation to the molecular potential, as shown by comparison with experiment, and with complete SCF calculations for CO, H2O, and H2S

Calculations of molecular ionization energies using a self‐consistent‐charge Hartree–Fock–Slater method

We use the atom-jellium model of chemisorption to study the properties of an atom bonded to the surface of a simple metal. Beyond the jellium simulation of the metal substrate and the Kohn-Sham local-density description of exchange and correlation, we make no significant approximations: our solutions are parameter free, wave mechanical, and fully self-consistent. We solve this model for a set of adatoms exhibiting a variety of chemical behaviors. Properties studied include the electron-density distribution, the state density, the dipole moment, and the heat of adsorption. We discuss also the reintroduction of the discrete lattice structure of the substrate using perturbation theory.

I.P. Batra

Papers

Cluster model calculations for electronic energy levels of oxygen chemisorbed on Ni