Electronic structure of transition metal

Wang L S and Wu H 1998 Probing the electronic structure of transition metal clusters from molecular to bulk-like using photoeieotron spectroscopy Cluster Materials, Advances In Metal and Semiconductor Clusters vo 4, ed M A Duncan (Greenwich JAI Press) p 299... 

Magnetic resonance methods in the study of the electronic structure of transition metal complexes. 

Electronic structures of transition metal cluster complexes. M. C. Manning and W. C. Trogler, Coord. Chem. Rev., 1981, 38, 89-138 (406). 

The electronic structure of transition metal cluster complexes with weak- and strong-field ligands. G. P. Kostikova and D. V. Korol kov, Russ. Chem. Rev. (Engl. Transl.), 1985,54, 344 (137). 

C.J. Ballhausen, Molecular Electronic Structures of Transition Metal Complexes, McGraw-Hill, New York, 1979. 

The best method available at the moment, to look at the electronic structure of transition metals and their alloys. Is probably... 

Introduction 231 Fundamental concepts 233 Electronic structure of transition-metal ions 235 Structural characteristics necessary for complex formation 240 Preparation of metal-complex colorants 248 Isomerism in metal-complex dyes 260 Stability of metal-complex dyes 261 Chromium-related problems in the mordant dyeing of wool 268 References 277... 

Electron correlation plays an important role in determining the electronic structures of many solids. Hubbard (1963) treated the correlation problem in terms of the parameter, U. Figure 6.2 shows how U varies with the band-width W, resulting in the overlap of the upper and lower Hubbard states (or in the disappearance of the band gap). In NiO, there is a splitting between the upper and lower Hubbard bands since IV relative values of U and W determine the electronic structure of transition-metal compounds. Unfortunately, it is difficult to obtain reliable values of U. The Hubbard model takes into account only the d orbitals of the transition metal (single band model). One has to include the mixing of the oxygen p and metal d orbitals in a more realistic treatment. It would also be necessary to take into account the presence of mixed-valence of a metal (e.g. Cu ", Cu ). 

Figure 6.52 Schematic electron addition and removal spectra representing the electronic structure of transition-metal compounds for different regimes of the parameter values (a) charge-transfer insulator with U > A (b) Mott-Hubbard insulator A> U (From Rao et al, 1992).

Analysis of the valence-band spectrum of NiO helped to understand the electronic structure of transition-metal compounds. It is to be noted that th.e crystal-field theory cannot explain the features over the entire valence-band region of NiO. It therefore becomes necessary to explicitly take into account the ligand(02p)-metal (Ni3d) hybridization and the intra-atomic Coulomb interaction, 11, in order to satisfactorily explain the spectral features. This has been done by approximating bulk NiO by a cluster (NiOg) ". The ground-state wave function Tg of this cluster is given by,... 

Ballhausen, C. J. Molecular Electronic Structure of Transition Metal Complexes McGraw-Hill New York, NY, 1979. 

As noted in Section 9.1, there are three closely related theories of the electronic structures of transition metal complexes, all making quite explicit use of the symmetry aspects of the problem but employing different physical models of the interaction of the ion with its surroundings as a basis for computations. These three theories, it will be recalled, are the crystal field, ligand field, and MO theories. There is also the valence bond theory, which makes less explicit use of symmetry but is nevertheless in accord with the essential symmetry requirements of the problem. We shall now briefly outline the crystal field and ligand field treatments and comment on their relationship to the MO theory. 

Figure 1.3 Electronic structure of transition metal carbides and nitrides. Band calculation reproduced from Hasegawa (Ref. 18).

In this chapter, we have developed the information content of different excited state spectroscopic methods in terms of ligand field theory and the covalency of L—M bonds. Combined with the ground-state methods presented in the following chapters, spectroscopy and magnetism experimentally define the electronic structure of transition metal sites. Calculations supported by these data can provide fundamental insight into the physical properties of inorganic materials and their reactivities in catalysis and electron transfer. The contribution of electronic structure to function has been developed in Ref. 61. 

Ballhausen, CJ (1979) Molecular electronic structures of transition metal complexes. McGraw-Hill, London... 

Considerable interest centres on the Mantle constituting, as it does, more than half of the Earth by volume and by weight. Attention has been focussed on several problems, including the chemical composition, mineralogy, phase transitions and element partitioning in the Mantle, and the geophysical properties of seismicity, heat transfer by radiation, electrical conductivity and magnetism in the Earth. Many of these properties of the Earth s interior are influenced by the electronic structures of transition metal ions in Mantle minerals at elevated temperatures and pressures. Such effects are amenable to interpretation by crystal field theory based on optical spectral data for minerals measured at elevated temperatures and pressures. 

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