Mossbauer absorption

Fig. 2.8 (a) Fractional absorption of a Mossbauer absorption line as function of the effective absorber thickness t. (b) The depth of the spectrum is determined by fs. The width for thin absorbers, t 1, is twice the natural line width F of the separate emission and absorption lines (see (2.30)). AE is the shift of the absorption line relative to the emission line due to chemical influence... 

Fig. 7.25 Mossbauer absorption spectra of Zn metal obtained at 4.2 K and at two different pressures. The source is Ga/Cu (from [75])...

Fig. 7.27 Mossbauer absorption spectra of a polycrystalline Znp2 absorber recorded between 4.2 and 55.3 K. The source, Ga in a ZnO single crystal, was kept at 4.2 K (from [81])...

Mossbauer spectroscopy with started only in 1965, when Harris et al. [322] measured the Mossbauer absorption spectra of the 99 keV transition of Pt in platinum metal as a function of temperature (between 20 and 100 K) and of absorber thickness and derived the temperature dependence of the Debye-Waller factor. 

Extensive knowledge of the behavior of gold molecular cluster compounds and colloids, with well-defined particle sizes, using Mossbauer absorption and... 

Fig. 8.21 (a, lifi) Pe Mossbauer absorption spectra of [ Fe/Co(phen)3](C104)2 as a function of temperature versus Co/Rh as source (which was kept at 295 K). (b, right) Time-integral Fe MossbauCT emission spectra of [ Co/Co(phen)3](004)2 source as a function of temperature... 

Fig. 9.18 Comparison of calculated time-domain spectra (NFS) and energy-domain spectra (Mossbauer absorption) for a-, b-, and c-cut single crystals of guanidinium nitroprusside. For the calculations the approximation of complete alignment of 14 parallel to the crystallographic c-axis is used. The polarisation direction of the synchrotron beam is represented by e. (Taken from [48])...

Physical properties of binary or ternary Ru/Ir based mixed oxides with valve metal additions is still a field which deserves further research. The complexity of this matter has been demonstrated by Triggs [49] on (Ru,Ti)Ox who has shown, using XPS and other techniques (UPS, Mossbauer, Absorption, Conductivity), that Ru in TiOz (Ti rich phase) adopts different valence states depending on the environment. Possible donors or acceptors are compensated by Ru in the respective valence state. Trivalent donors are compensated by Ru5+, pentavalent acceptors will be compensated by Ru3+ or even Ru2+. In pure TiOz ruthenium adopts the tetravalent state. The surface composition of the titanium rich phase (2% Ru) was found to be identical to the nominal composition. 

Mossbauer Absorption Spectroscopy (MAS) Mossbauer Emission Spectroscopy (MES)... 

The ferric oxide, hematite, used in the present work was a high purity powder reagent with a BET surface area of 27 m2/g 30 mg was employed in each run. Some measurements were made on hematite calcined in air to see the effects of sintering the surface on the chemical structure of the adsorbed metal ions. The hematite samples were checked by Mossbauer absorption and powder X-ray diffraction measurements. The Mossbauer absorption spectra consisted of a magnetic sextet with no superparamagnetic component due to fine particles ( ). 

In parallel with the emission measurements, in situ Mossbauer absorption measurements on hematite suspensions treated in a similar manner as in the emission measurements were performed to check the effects of aqueous phase pH on the substrate. The absorption spectra obtained in the pH region 5-12 consisted of the same well-defined sextet as dry hematite powder, indicating that no appreciable change occurred in the state of dispersion and particle size of hematite in the studied pH range. 

Polyakov 1997). Because the second-order Doppler shift is not the only factor controlling Mossbauer absorption frequencies, it is generally necessary to process data taken at a variety of temperatures, and to make a number of assumptions about the invariance of other factors with temperature and the form and properties of the vibrational density of states of the Mossbauer atom. Principles involved in analyzing temperature dependencies in Mossbauer spectra are extensively discussed in the primary literature (Hazony 1966 Housley and Hess 1966 Housley and Hess 1967) and reviews (e.g., Heberle 1971). 

Figure 3. Mossbauer absorption spectra of aconitase at 4.2 K in zero field. (A) Dithionite reduced enzyme activated with 99.9% enriched Fe. (B) Dithionite reduced enzyme activated with >90% enriched Fe. (C) Apoaconitase incubated with dithionite and Fe. (Reproduced with permission from ref. 39. Copyright 1982 the authors.)...

Fig. 4. Mossbauer absorption spectra of hemoglobin fluoride at a) 4 °K, background 40%, and b) 1.2 °K, background 40%.

Fig. 6. 57Fe Mossbauer absorption spectra of [Fe(phen)2(NCS)2] as a function of temperature (P, Ganguli, P. Gutlich, W. MUller, unpublished)...

FIGURE 4.58 57Fe Mossbauer absorption spectrum resulting from isomer shift. 

Figure 2. Typical Mossbauer absorption spectrum obtained with a 195Au in a Pt matrix source and a 0.0063-inch thick Pt absorber both source and absorber were at 20°K (9)...

Fig. 11.8 Mossbauer absorption spectrum of Japanese radish peroxidase a-hydrogen peroxide Compound III at (a) 77°K and (b) 195°K. Reproduced with permission from [145]...

Since the electric quadrupole moment of the nuclear ground state of iron Fe with /g = 1 /2 is zero, the quadrupole interaction does not affect the ground state, but splits the first excited nuclear state with 4 = 3/2 into two sublevels. As a result, it produces, in the case of Fe, a two-line Mossbauer absorption pattern (Figure 4) with a corresponding quadrupole sphtting AEq given by... 

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