Isotopes Mdssbauer spectroscopy

The ground- and excited-state magnetic moments ji are tabulated as /ig = 0.09062(3) n.m. (nuclear magnetons, /i ) and jig, = 0.1549 n.m., respectively (see Table Properties of Isotopes Relevant to Mdssbauer Spectroscopy provided by courtesy of Professor J. G. Stevens, Mdssbauer Effect Data Center, cf. CD-ROM). Considering that nuclear magnetic moments are given by the relation p, = giPj I, the nuclear g factors for Ee with /g = 1/2 and 1 = 3/2 are gg = 0.09062 X 2 and ge = 0.1549 x 2/3. With these values and taken from... 

Although GEMS is a more difficult technique experimentally than normal Mdssbauer spectroscopy it offers many exciting possibilities for the study of Mdssbauer isotopes on or near the surface. It could be a useful technique to study the properties of bifunctional zeolite catalysts and metal-impregnated zeolite catalysts. 

The nucleus of an isotope suitable for Mdssbauer spectroscopy must have an excited state of moderately low energy (less than about 200 keV) to permit the occurrence of recoilless emission and absorption, and the excited state must be accessible, preferably by the spontaneous decay of a parent isotope with a... 

The term microenvironment is of fundamental importance in M5ssbauer spectroscopy. It is directly related to the hyperfine interactions sensed by the nucleus. In a solid studied by Mdssbauer spectroscopy, there are a large number of nuclei of the M5ssbauer isotope. They all sense local hyperfine interactions, which are determined by the product of a nuclear parameter (charge equivalent nuclear radius, Ry nuclear quadrupole moment, Q, and nuclear magnetic moment, /r) and a solid-state parameter (electronic density, p, electric field gradient represented by V22 and rj, and magnetic flux density, B) (see OEqs. (25.60), (0 25.68), and (025.74)). 

The existence of a proper y-ray transition is an outcome of nuclear structure. Therefore, a Mdssbauer transition is coupled to a certain isotope of the atom of interest. A low isotopic abundance of the resonant isotope may be a serious restriction. Next, if the excited state is rather short lived then F becomes wide and the resolution for hyperfine spectroscopy (see section 2.3) becomes too limited. The same effect can be caused by unfortunate values of nuclear moments of the two states involved in the Mdssbauer transition. Finally, difficulties to produce the source activity may hinder a wider application of measurements with that particular isotope. Difficulties in source preparation and poor resolution are, for example, present in and have prevented Mdssbauer spectroscopic studies of compounds of this most interesting actinide. 

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