Mossbauer selected parameters

A CD-ROM is attached containing a teaching course of Mossbauer spectroscopy (ca. 300 ppt frames), a selection of examples of applications of Mossbauer spectroscopy in various fields (ca. 500 ppt frames), review articles on computation and interpretation of Mossbauer parameters using modem quantum-mechanical methods, list of properties of isotopes relevant to Mossbauer spectroscopy, appendices refering to book chapters, and the first edition of this book which appeared in 1978. In subsequent printmns files are available via springer.extra.com (see imprint page). 

Table 5. Selected Mossbauer parameters for ferrocene and various open ferrocenes (mm/s)...

Supported non-framework elements, as well as substituted or doped framework atoms, have been important for zeolite catalyst regeneration. By incorporating metal atoms into a microporous crystalline framework, a local transition state selectivity can be built into the active site of a catalytic process that is not readily attainable in homogeneous catalysis. The use of zeolites for carrying out catalysis with supported transition metal atoms as active sites is just beginning. The local environment of transition metal elements as a function of reaction parameters is being defined by in situ Mossbauer spectroscopy, electron spin echo measurements, EXAFS, and other novel spectroscopic techniques. This research is described in the second part of this text. 

Table 22 Mossbauer Parameters for Iron(II) Phthalocyanine and Selected Derivatives at Room and Liquid Nitrogen Temperatures...

The aim of this chapter is to provide a brief background to Mossbauer spectroscopy within the context of phase transformations. The relevant parameters are summarised and the effect of temperature and pressure are discussed, particularly with reference to identifying phase transformations and characterising the electronic and structural environment of the Mossbauer nuclei. Instrumentation is summarised, particularly as it relates to in situ measurements of phase transformations, and a brief survey of applications is given. The appendix includes a worked example that illustrates the methodology of investigating a phase transformation using in situ Mossbauer spectroscopy. Numerous textbooks and review chapters have been written on Mossbauer spectroscopy, and a selection of the most relevant ones as well as some useful resources are listed in Table 1. 

Christie et al. (53) reported data on the catalytic performance which may also be related to the solid state properties of tin-antimony oxide. A material containing 6% antimony in a batch reactor showed maximized specific activity and low selectivity toward propylene. Above 10% antimony the selectivities exceeded 60% and increased little with increasing antimony content. It is interesting that the " Sn Mossbauer parameters (17) showed similar trends, which were attributed to effects in the solid solution. 

Several haemin type compounds have been examined [1, 3, 4], and selected Mossbauer parameters are given in Table 13.1. The haemin chlorides of protoporphyrin IX, 2,4-diacetyldeuteroporphyrin IX dimethyl ester, and mesoporphyrin IX, and haematin all show a characteristic broadening of one of the resonance lines with rising temperature. This is dramatically illustrated in Fig. 13.2 for the deuterohaemin compound. In all cases they are Fe(III) 5 = f compounds. 

Research workers investigating the solvent effect selected model systems with some well measurable property (e.g., light absorption in the UV, visible or IR spectrum, heat of formation, an NMR, Mossbauer or NQR parameter, the redox potential, reaction rate, etc.) which changes appreciably due to the effect of the solvent. Hence, these experimentally measurable data, characteristic of the extent of the interaction between the solvent and the solute, may serve to categorize the solvating powers of solvents. Of course, solvent scales obtained in this way can be compared with one another only if the solvation process in the different model systems is governed by analogous factors. 

On the basis of Mossbauer studies on frozen solutions of iron(II) salts in various non-aqueous solvents. Burger et al. [Bu 70] drew conclusions about the structures of the iron(II) solvates. High-spin iron(II) salts were selected as their first model system, as the Mossbauer parameters here, and primarily the high quadrupole splitting, are sensitive indicators of even small changes in the electronic configuration of the iron. 

TABLE 15.1 Mossbauer Parameters of Selected Heme-Based Fe(IV)=0 Species ... 

The coal used in this investigation originated from the Landau mine in the Mpumalanga/Witbank area and was specially selected due to the different sulfur content (0.6 and 3.0%, respectively) observed in the selected coal samples, the sulfur being present mainly in the mineral pyrite (see Fig. 30.10). The Mossbauer parameters are shown in Table 30.2. 

Selected Mossbauer parameters for the iron pyridine complexes are... 

Table 6.1 Nuclear parameters for selected Mossbauer isotopes.

Chapter 2 is devoted to chemical applications of Mossbauer spectroscopy, and the authors are Philipp Giitlich and Yann Garcia. They begin with a brief reca-pimlation of the hyperfine interactions and the relevant parameters observable in a Mossbauer spectrum. The main chapter with selected examples of chemical applications of Mossbauer spectroscopy follows and is subdivided into sections on Basic information on structure and bonding, switchable molecules, mixed-valence... 

All hyperfine parameters of the atoms near the surface can be different fi-om the hyperfine parameters of the atoms in the interior. In general, however, surface and bulk contributions are not clearly differentiated from each other. Because of the great variety of surface sites, the hyperfine parameters of the surface atoms, especially the hyperfine field, can be broadly distributed. These distributions combine with the effects of the distributions of particle size and shape, often making surface and volume effects difficult to distinguish from one another. Investigations based on the isotope selectivity of Mossbauer spectroscopy may then be particularly useful. 

Although the aim of this chapter is to show how a thermodynamic relationship between A and AI allows to predict the type of catalysts needed for a reaction, it is worth recalling that A can be correlated with experimental parameters related to catalysis, or values of selectivity, provided the same reaction is studied [33]. For example, by using data proposed by Matsuura [60], the heat of adsorption A//ads for a series of catalysts of oxidation of 1-butene to butadiene, or the Mossbauer quadruple shift values for Fe +-containing catalysts of propene ammoxidation, could be related to the A value of the respective catalysts [33]. In a study of the ODH... 

Parameters of selected Mossbauer resonances in lanthanides and actinides. 

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