Silver electronic structure

In TT-complexes formed from aromatic compounds and halogens, the halogen is not bound to any single carbon atom but to the 7r-electron structure of the aromatic, though the precise geometry of the complexes is uncertain. The complexes with silver ions also do not have the silver associated with a particular carbon atom of the aromatic ring, as is shown by the structure of the complex from benzene and silver perchlorate. ... 

Phenylmercury derivatives of 3-aminomethylene-l-methyloxindols have also been investigated (79KGS65). For studies of the effect of substituents on the electronic structure of silver and potassium salts of 3-(aryl)imi-nooxindole see 76MI2. The keto-enol and imino-enamine tautomerism of compounds of type 127 (with 128 and 129) has been investigated (85KGS921). 

In Section 2 the general features of the electronic structure of supported metal nanoparticles are reviewed from both experimental and theoretical point of view. Section 3 gives an introduction to sample preparation. In Section 4 the size-dependent electronic properties of silver nanoparticles are presented as an illustrative example, while in Section 5 correlation is sought between the electronic structure and the catalytic properties of gold nanoparticles, with special emphasis on substrate-related issues. 

In spite of the similarity of electronic structures and ionization potentials, the chemistries of Ag and Au differ more than might be expected. Main differences between silver and gold are... 

Figure 6.25. Valence band photoemission spectra of 1 ML Ceo on a Ag(lOO) surface as a function of potassium doping. Also shown are the spectra of the clean Ag(lOO) surface and of a Ceo multilayer (bottom). All binding energies are referred to the L f of polycrystalline silver. Reprinted from Surface Science, Vols. 454-456, C. Cepek, M. Sancrotti, T. Greber and J. Osterwalder, Electronic structure of K doped Ceo monolayers on Ag(OOl), 467 71, Copyright (2000), with permission from Elsevier.

All of the studies discussed above for silver have been done with an incident beam of 1064 nm. These studies have proven that the anisotropy in the nonlinear polarizability from the silver surface is not purely free-electron-like at these wavelengths, that the anisotropy can be correlated with surface symmetry, and that the SH response measured in situ is nearly identical to that measured in UHV. The issue of the sensitivity of the rotational anisotropy to surface electronic properties has been the topic of very recent work which has been conducted by variation of the incident wavelengths to where optical resonances in the bulk or surface electronic structure can be accessed. 

Shaw, J. L., Wolowska, J., Collison, D., etal., Redox non-innocence of thioether macrocycles Elucidation of the electronic structures of mononuclear complexes of gold (II) and silver(II). J Am. Chem. Soc. 2006, 128, 13827-13839. 

Figure 10.2. Electron micrographs of typical colloidal gold and silver particle structures used in SERS experiments. (a) Colloidal gold particles in the isolated and aggregated stage after addition of NaCl. (b) Typical colloidal silver clusters exhibiting strong SERS enhancement. (With permission from Refs. 17 and 18.)...

As for Raman spectroscopy one may expect resonance Raman effect and/or surface-enhanced Raman scattering (SERS). By using these effects, the Raman spectrum of a monolayer film may be enhanced by 103-106. Resonance Raman spectroscopy is useful for exploring the electronic structure of monolayers with a chromophore and SERS technique is applied to study structure, orientation, and interactions of monolayers on a silver or gold surface. 

Like copper, silver and gold have a single s electron outside the completed d shell, but in spite of the similarity in electronic structures and ionization potential, the chemistries of Ag, Au, and Cu differ more than might be expected. There are no simple explanations for many of the differences although some of the differences between Ag and Au may be traced to relativistic effects on the 6s electrons of the latter. The covalent radii of the triad follow the trend Cu < Ag Au, i.e., gold has about the same or a slightly smaller covalent radius than silver in comparable compounds, a phenomenon frequently referred to as relativistic contraction (c/. lanthanide contraction). 

Early calculations for copper, palladium, and silver clusters were carried out by various investigators using the EH and CNDO methods, and among these is an attempt by Baetzold to take into account the effect of a carbon support on the electronic structure of a palladium cluster.In 1976, Messmer etal. compared the efficacies of the three methods of calcu-... 

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