Mössbauer Isomer Shifts of the 6.2-keV Gamma Rays of Tantalum-181

Kaindl, G.; Salomon, D.; Wortmann, G.

doi:10.1007/978-1-4684-3162-9_13

Cited by 13 publications

(8 citation statements)

References 31 publications

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“…Figure 10.5 shows isomer shift data for 99 Ru, 193 Ir and 195 Pt alloyed into 3d , 4d , and 5d metals [45]. Similar data exist for 57 Fe and 197 Au [45,48], and to a lesser extent for 181 Ta [49]. Taking the sign and magnitude of hr 2 i into account, one finds that the electron densities at all these Mössbauer nuclei depend in much the same way on the host lattice, whose electron structure and lattice volume appear to be the main properties affecting the isomer shifts.…”

Section: Isomer Shifts In D Transition Elementssupporting

confidence: 58%

“…General features of these transitions are discussed elsewhere in this volume [44]. The isomer shifts observed in these resonances have been reviewed some time ago [22,[45][46][47]49]. More recent results added some additional aspects but did not seriously change the general picture of isomer shifts in the d transition elements, which show some rather general behavior.…”

Section: Isomer Shifts In D Transition Elementsmentioning

confidence: 92%

“…They fit well into the general picture [45]. The 6.2 keV resonance in 181 Ta yields large isomer shifts compared to the narrow linewidth, but due to experimental difficulties mainly metallic systems have been studied [49].…”

Section: Isomer Shifts In D Transition Elementsmentioning

confidence: 96%

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Isomer Shifts in Solid State Chemistry

Wagner

Stievano

2011

The Rudolf Mössbauer Story

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The isomer shift of the Mössbauer resonance is a rather unique quantity that cannot be obtained by any of the other techniques used for measuring hyperfine interactions in solids, such as NMR or perturbed angular correlations (TDPAC). It shifts the resonance pattern as a whole without affecting the magnetic dipole and electric quadrupole hyperfine splittings. Methods that measure only these hyperfine splittings are insensitive to the isomer shift. The magnitude of the observed shift is proportional to the product of a nuclear parameter, the change hr 2 i of the nuclear radius that goes along with the Mössbauer transition, and to an electronic property of the material, the electron density .0/ at the Mössbauer nucleus or, more precisely, to the difference .0/ of the electron densities at the Mössbauer nuclei in the materials of which the source and the absorber are made. The electron density at the nucleus is due to s-electrons and, to a lesser extent and mainly in heavy nuclei, to relativistic p 1=2 -electrons. All the other electrons have a vanishing density inside the nucleus and do not contribute. Thus, to a very good accuracy, the Mössbauer isomer shift enables one to obtain information on the s-electron density at the Mössbauer nuclei in solids.The isomer shift thus yields important insights into the chemical bonding in solids. For instance, it often allows an easy distinction between different oxidation states of an element, e.g., between divalent and trivalent iron or divalent and tetravalent tin. The s-electron densities are also sensitive to covalency in chemical compounds and to effects of band structure in metals. For this reason, the isomer

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Section: Isomer Shifts In D Transition Elementssupporting

confidence: 58%

Section: Isomer Shifts In D Transition Elementsmentioning

confidence: 92%

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Isomer Shifts in Solid State Chemistry

Wagner

Stievano

2011

The Rudolf Mössbauer Story

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“…9 Since the electron density at the nucleus, l# 0 I 2 , should decrease with increasing volume, we expect positive values for (85 IS /a lnF) r in all cases, even though their magnitudes might exhibit large variations, as observed in the case of 57 Fe. There, isomer shifts have been measured as a function of pressure for impurities of 57 Fe in a series of 3d, Ad, and 5d transition-metal hosts, 12 and (8S K /8 \nV) T was found to increase with decreasing isomer shift (or increasing l^0l 2 ), as expected from a scaling of l# 0 I 2 with volume.…”

Section: Blnv) Tmentioning

confidence: 69%

“…Recently this resonance has been applied extensively to high-resolution studies of hyperfine interactions, 8 and its especially high resolving power in the field of isomer shifts has been recognized. 8 ' 9 We have now found that the energy of the 6.2-keV y rays, emitted from 181 Ta as a dilute impurity in transition metals, exhibits a strong temperature dependence far beyond the expected SOD shift. The results underline the exceptional sensitivity of the 6.2-keV y resonance, and open new possibilities in solid-state applications of isomer-shift studies.…”

mentioning

confidence: 81%

Effects of Temperature on the Energy of the 6.2-keV MössbauerγRays ofTa181

Kaindl¹,

Salomon²

1973

Phys. Rev. Lett.

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We have found a strong temperature dependence of the energy of the 6.2-keV y rays from dilute impurities of 181 Ta in transition-metal hosts. The observed temperature shifts cover a range of -32 to +8 times the expected thermal red shift, and exhibit large variations with the hosts. The effects of temperature on the energy of Mossbauer y rays have been studied up to now in detail only for 57 Fe 1M and 119 Sn. 5 For both these Mossbauer resonances the observed variations with temperature are mainly caused by the second-order Doppler (SOD) effect (thermal red shift). 6 Accordingly, information on the variation of the total electron density at the nucleus with temperature could be derived only after dominant corrections for the thermal red shift had been made 5 ' 7 ; therefore, this procedure may have introduced large systematic errors, limiting the accuracy of the derived results.The case of the 6.2-keV y resonance of 181 Ta is quite different, as will be reported in the present paper. Recently this resonance has been applied extensively to high-resolution studies of hyperfine interactions, 8 and its especially high resolving power in the field of isomer shifts has been recognized. 8 ' 9 We have now found that the energy of the 6.2-keV y rays, emitted from 181 Ta as a dilute impurity in transition metals, exhibits a strong temperature dependence far beyond the expected SOD shift. The results underline the exceptional sensitivity of the 6.2-keV y resonance, and open new possibilities in solid-state applications of isomer-shift studies.

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