X-ray photoelectron studies on some oxides and hydroxides of cobalt, nickel, and copper

Publisher Summary This chapter discusses statistical exchange-correlation in the self-consistent field. There are two sides to a self-consistent field calculation: the determination of the potential and the solution of Schrodinger's equation for the one-electron problem. The solution of Schrodinger's equation has fortunately advanced far enough through the application of the electronic digital computer so that it can be regarded for most purposes as being a standardized technique. The main point of the method of Gaspar, Kohn, and Sham is that they derive the approximate exchange correction from an approximate Hamiltonian for the system by varying the spin-orbitals to minimize the average value of this Hamiltonian for the ground state. The approximate Hamiltonian has many important and valuable features that are described in the chapter.

Statistical Exchange-Correlation in the Self-Consistent Field

Iron-based Fischer–Tropsch catalysts, which are applied in the conversion of CO and H2 into longer hydrocarbon chains, are historically amongst the most intensively studied systems in heterogeneous catalysis. Despite this, fundamental understanding of the complex and dynamic chemistry of the iron–carbon–oxygen system and its implications for the rapid deactivation of the iron-based catalysts is still a developing field. Fischer–Tropsch catalysis is characterized by its multidisciplinary nature and therefore deals with a wide variety of fundamental chemical and physical problems. This critical review will summarize the current state of knowledge of the underlying mechanisms for the activation and eventual deactivation of iron-based Fischer–Tropsch catalysts and suggest systematic approaches for relating chemical identity to performance in next generation iron-based catalyst systems (210 references).

The renaissance of iron-based Fischer-Tropsch synthesis: on the multifaceted catalyst deactivation behaviour.

Core-level binding-energy shifts at surfaces and in solids

Charge transfer in transition metal carbides and related compounds studied by ESCA

X-ray study of inner level shifts and band structure of TiC and related compounds

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Conductometric and Dielectric Behaviour of Solutions of Tetrabutylammonium Perchlorate in Solvents of Low and Medium Permittivity.

The K?1?' structure is investigated experimentally for all pure elements of the first transition series and for some of their compounds. Analogous structures are found for L emission spectra of some second transition series elements as well as of some lanthanides. Relative transition energies and probabilities are calculated in a frozen-orbital approximation for the transition from a normal K state to singly ionized states of the configuration 3p53dn4s2 for the elements Sc-Ni. The results support the interpretation that the K?1?' structure is due to the electron interaction between partially filled 3p and 3d subshells. The electron interaction mechanism also explains the effects in the heavier elements investigated.

Electron Interaction in Transition Metal X-ray Emission Spectra

X-ray emission spectra of VCx, NbCx, TaCx, and ZrC

Dielectric properties of solutions of tetra-iso-pentylammonium nitrate, i-Pen 4 NNO 3 . in various dioxane-water mixtures have been studied using dielectric time domain spectroscopy (TDS). The static permittivity of the solutions ɛs increases for low concentrations of solute but levels off to asymptotic values at higher concentrations. The limiting slopedɛsdc, and the asymptotic value depend on the static permittivity of the solvent mixture. The relaxation time due to the solute varies with solute concentration and depends on the solvent mixture. In the solvent mixtures of lowest permittivity the plots of relaxation time vs. concentration go through a maximum, while in the mixtures of highest permittivity the relaxation time initially decreases and then levels off to an asymptotic value. The concentration dependence of the dielectric parameters is discussed in relation to ion association.

Erik Noreland

Papers

X-ray study of inner level shifts and band structure of TiC and related compounds

Conductometric and Dielectric Behaviour of Solutions of Tetrabutylammonium Perchlorate in Solvents of Low and Medium Permittivity.

Electron Interaction in Transition Metal X-ray Emission Spectra

X-ray emission spectra of VCx, NbCx, TaCx, and ZrC

Dielectric properties of solutions of tetra-iso-pentylammonium nitrate in dioxane-water mixtures