Applications of Mossbauer spectroscopy

From its beginnings as an elegant experiment in nuclear and solid state physics Mossbauer spectroscopy has come to be applied to different problems in many areas of science and technology. The interdisciplinary nature of the technique and its numerous applications are illustrative both of the way in which science develops and of how it leads to technological progress. As a means of investigation it successfully complements other experimental methods but has several features which make it an especially powerful technique in a number of important situations and applications. 

Although the diversity of potential applications of Mossbauer spectroscopy is too extensive to detail here, it is relevant to mention a few of the fields in which the technique has been found to be particularly useful. Metallurgy has proved to be an important area which has benefited from the application of this technique, indeed Fe Mossbauer spectroscopy has developed as a valuable experimental method in steel research and commercial operation as a means by which the iron phase distributions both in ores and in processed steel can be monitored. 

Catalysis is a multi-disciplinary area of science and within this large field several regions of interest have been found to be amenable to investigation by Mossbauer spectroscopy. A particularly successful application of Mossbauer spectroscopy within this field has involved the in situ study of solids which catalyse gaseous reactions. The development of special cells in which these catalysts may be studied in their authentic working environment is an important feature of this work. In many of the Mossbauer spectroscopic studies of catalysts the data have been used in conjunction with that from other techniques to elucidate fundamental properties of both the bulk and surface which influence catalytic performance. 

The study of solid surfaces has provided another area of application in 

Mossbauer spectroscopy has also found considerable applications in the investigation of mineral systems. Much of this work has involved the determination of the number and structure of the chemical phases within certain minerals and has been of both scientific and technological importance. The importance of small amounts of doping and impurities in affecting the Mossbauer spectrum provides a significant feature of much of this work. 

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Product yields may also be determined by magnetic measurements, as in the formation of ferrites [340], where kinetic data were obtained at reaction temperature. Quantitative applications of Mossbauer spectroscopy have also been described [326]. 

Chemical applications of Mossbauer spectroscopy. R. H. Herber, Prog. Inorg. Chem., 1967,8,1-41 (108). 

The application of Mossbauer spectroscopy in the study of mixed ligand complexes. K. Burger, Inorg. Chim. Acta, Rev., 1972, 6, 31-46 (125). 

The example is typical for many applications of Mossbauer spectroscopy in catalysis a catalyst undergoes a certain treatment, then its Mossbauer spectrum is measured in situ at room temperature. Flowever, if the catalyst contains highly dispersed particles, the measurement of spectra at cryogenic temperatures becomes advantageous as the recoil-free fraction of surface atoms increases substantially at temperatures below 300 K. Secondly, spectra of small particles that behave superparamagne-... 

Applications of Mossbauer Spectroscopy" Cohen, R.L. Ed. Academic Press New York, 1980. 

Goldanskii, V.I., Herber, R. (eds.) Chemical Applications of Mossbauer Spectroscopy. Academic, New York (1968)... 

An important accessory in many applications of Mossbauer spectroscopy is a cryostat for low temperature and temperature-dependent measurements. This may be necessary to keep samples frozen or to overcome small Debye-Waller factors of the absorbers at room temperature in the case of an isotope with high y-energy. Paramagnetic samples are measured at liquid-helium temperatures to slow down... 

The application of Mossbauer spectroscopy in chemistry requires a prior knowledge of the nuclear states and transitions involved. In this section, we shall describe the determination of nuclear parameters by means of Mossbauer experiments with Os nuclei. 

A number of publications deal with Au Mossbauer studies of various gold alloys. As the primary goal of this review is directed towards applications of Mossbauer spectroscopy to chemical compounds rather than metallic systems, we present here a brief enumeration of most of the work by giving reference to relevant publications and providing a note concerning the essential points of interest in each case ... 

The reader is also referred to the CD-ROM enclosed at the end of this book, where we have collected a large variety of examples of applications of Mossbauer spectroscopy in many disciplines. The first part of the CD-ROM presents a lecture series on Mossbauer spectroscopy (Principles and typical applications), which has been arranged particularly for teaching purposes. The second part comprises a large number of special applications contributed by various research groups specialized on Mossbauer spectroscopy. 

Mossbauer spectroscopy is particularly suitable to study ST since (1) the spectral parameters associated with the HS and LS states of iron(II) clearly differ and (2) the time-scale of the technique ( 10 s) allows the detection of the separate spin states in the course of the transition. Typically, Mossbauer spectra of HS iron(II) show relatively high quadrupole splitting (AEq 2-3 mm s ) and isomer shift (3 1 mm s ), while for LS iron(II), these parameters are generally smaller (AEq < 1 mm s 3 < 0.5 mm s ). Among the early applications of Mossbauer spectroscopy to study ST phenomena in iron(II) complexes is the work of Dezsi et al. [7] on [Fe (phen)2(NCS)2] (phen = 1,10-phenanthroline) as a function of temperature (Fig. 8.2). The transition from the HS ( 12) state (quadrupole doublet of outer two lines with AEq 3 mm s ) to the LS CAi) state (quadrupole... 

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). 

Longworth, G. and S. E. Warren (1979), The application of Mossbauer spectroscopy to the characterization of western Mediterranean obsidian,. Archaeol. Sci. 6, 1-15. 

Rather sophisticated applications of Mossbauer spectroscopy have been developed for measurements of lifetimes. Adler et al. [37] determined the relaxation times for LS -HS fluctuation in a SCO compound by analysing the line shape of the Mossbauer spectra using a relaxation theory proposed by Blume [38]. A delayed coincidence technique was used to construct a special Mossbauer spectrometer for time-differential measurements as discussed in Chap. 19. 

The application of Mossbauer spectroscopy to the investigation of catalysts began around 1970. By 1990, over 600 scientific papers had been published [18]. Most applications of Mossbauer spectroscopy to catalysts fall in one of the following categories ... 

Several books (J, 16,18, 31, 37), review articles (7,11—15,17, 20, 22, 24, 25, 38), and symposia (9, 23, 32) have been published that are valuable as an introduction to those interested in the application of Mossbauer spectroscopy to chemical and biochemical problems. 

Applications of Mossbauer spectroscopy to strictly chemical problems of the lanthanides have been few. Nevertheless, some interesting chemical relationships can be derived from physical work—e.g., that of Hiifner on The relative... 

Magnetic microcrystals. In Cohen, R.L. (ed.) Applications of Mossbauer spectroscopy. Academic Press, New York, 2 1-53 Morup, S. Madsen, M.B. Franck, J. Villadsen,... 

N. N. Greenwood, "Chemical and Biological Applications of Mossbauer Spectroscopy, Endeavour 27, 33 (1968). 

Because the greatest limitation for the general use of Mossbauer spectroscopy is that it cannot be observed for all elements, those criteria which restrict the application of Mossbauer spectroscopy to certain isotopes will be discussed in detail in Section II, A. Here, it will be shown which of these Mossbauer isotopes may be used to obtain chemical information, and how these isotopes may also be used to obtain in an indirect manner similar information about elements for which there exists no Mossbauer effect. 

Due to effects caused by the nuclear decay in the sample, these so-called source experiments may be difficult to perform and interpret. Several papers dealing with these effects can be found (23). In principle, however, the applicability of Mossbauer spectroscopy to catalytic studies can be extended to include both the Mossbauer isotopes and the corresponding parent nuclides. We therefore list below the Mossbauer isotopes and corresponding parent nuclides that may be of greatest use in catalytic studies, as deduced from their nuclear properties. 

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