Quadrupole interaction studies of Hg in Sb

Krien, K.; Herzog, P.; Folle, H. R.; Freitag, Κ.; Reuschenbach, F.; Reuschenbach, M.; Trzcinski, R.

doi:10.1007/bf01351550

Cited by 17 publications

(3 citation statements)

References 16 publications

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“…The tendency that the normalized EFGs generally decrease going from As through Sb to Bi as matrix is seen as a direct con sequence of the decreasing deviation from close packing. A disturbing fact is the observation that in Sb opposite signs for the EFG of Hg and Cd have been measured [39,40]. If these data stand an experimental test, a systematic behaviour would be very hard to find for these semimetals.…”

Section: Semimetalsmentioning

confidence: 99%

Quadrupole Interaction in Metals: Nuclear Methods

Haas

1986

Zeitschrift Für Naturforschung A

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Nuclear techniques offer the unique possibility to investigate the hyperfine interaction at isolated im purities in matter. Electric field gradients at impurities in metals have now been determined in numerous systems. An overview o f the various techniques -perturbed angular correlation/distribution. M össbauer spectroscopy, nuclear orientation -is presented. For spimpurities in sim ple metals the results show a very clear pattern that can be understood in terms o f the local density o f states. Several recent applications o f nuclear methods to more complicated systems like alloys, point defects, diffusion, and surfaces are discussed. A) Methods Historical IntroductionOne of the most im portant discoveries o f atom ic physics was the observation of the splitting of optical lines by the interaction of the electrons with the nuclear moments. For many years the m easure ment of this hyperfine interaction was only possible in free atoms. The determ ination of nuclear spins, magnetic moments, and later quadrupole moments of stable ground states has been very im portant in the process of achieving an understanding o f the structure of nuclei.The detection of N M R in condensed m atter [1] opened up a completely new field, the use of nuclear moments in the investigation of liquids and solids. Four years later followed the first deter minations of quadrupole coupling constants [2], The electric field gradient, EFG, is actually one of the most informative aspects of hyperfine interactions in solids we know today.Not or the use of particle accelerators was necessary, only few laboratories could perform such experi ments. When the M ößbauer effect was discovered [7], if found almost immediate w idespread applica tion, largely due to the fact that the solid samples studied did not have to contain radioactivity.The steady improvement in experimental equip ment and facilities has now led to the situation that all the nuclear techniques, historically more direct ed toward nuclear moment measurements, can be routinely applied for solid state studies. Since generally only a small num ber of probe atoms ( 10 8-10 14) are needed and high energy radiation is detected, these methods are especially suited for the investigation of impurities, primarily in metals. The internal magnetic field at impurities are of great value in all studies of magnetism, a very active area of solid state physics at present. This review is con cerned with the quadrupole interaction at im pu rities in metals, perhaps the most im portant con tribution of the nuclear methods, particularly when the many applications are considered. Overview of MethodsIn all studies of hyperfine interactions in solids one measures the splitting of the nuclear sublevels in the field acting on the nucleus. The techniques may be classified according to the way in which these energy separations, typically of order 100 MHz, are determined: a) Direct spectroscopy (N M R /N Q R ): Quanta corresponding to the transition energy are absorbed, emitted or scattered by the system. For RF...

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Section: Semimetalsmentioning

confidence: 99%

Quadrupole Interaction in Metals: Nuclear Methods

Haas

1986

Zeitschrift Für Naturforschung A

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“…As shown by Soares et al [22] the amount of the enhancement factor K depends on the valency of the impurity. In [223 the electronic enhancement factors obtained for different impurities in a Zn matrix, were plotted versus the nominal valency of the impurities.…”

Section: Quadrupole Interactionmentioning

confidence: 88%

“…Assuming such a linear correlation, the enhancement factor K should reach values between 1.8 and 3 for an impurity valency between Z= + 1 and Z= +2, respectively. From an analysis of field gradients measured on Hg impurities in different metal hosts, in [22] K was determined to be 1.4. The lower value for K in the case of Hg as indicated by a linear correlation was interpreted as a release of less valence electrons into the conduction band as would be expected for the assumed Valence for the Hg ion of Z= +2.…”

Section: Quadrupole Interactionmentioning

confidence: 99%

199Hg M�ssbauer measurements on mercury alloys and Hg-fluorides

Wurtinger

Kankeleit

1979

Z Physik A

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The M6ssbauer effect on the 158 keV 5/2--1/2-transition in 199Hg, of the order of 10 ppm, has been studied using the current integration technique. The isomer shift between the Hg(I)-and Hg(II)-fluorides as well as the quadrupole splitting in Hg2Pt and HgzF 2 are interpreted in terms of relativistic Hartree-Fock-Slater and Molecular Orbital calculations. The following nuclear parameters could be derived:A (r2) Evidence for an oblate triaxially deformed 199Hg nucleus is derived from particle plus rotor calculations.

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Electric Quadrupole Interaction in Noncubic Metals

Witthuhn¹,

Engel²

1983

Topics in Current Physics

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With 39 FiguresThe knowledge of the charge distribution is of basic importance for the detailed understanding of the properties of a solid. In noncubic solids this charge distribution creates an electric field gradient (EFG). The quadrupole hyperfine interaction (QI) between the nuclear quadrupole moment Q and the EFG at the site of the nucleus results in an energy-splitting of the nuclear levels. The investigation of this QI in noncubic metals and alloys can be carried out by a variety of experimental techniques. The application of the perturbed angular correlation methods has been especially fruitful in this field. Its advantages, essential for QI studies in metals, are the ease with which temperature and pressure dependencies can be measured and the applicability to pure metals as well as to systems with extremely diluted impurity probe atoms. Thus, most experimental data have been obtained by this technique during the last few years.The first experiments on the EFG in metals were reported more than two decades ago [S. I-3]. The interest in this field increased drastically after the pioneering work of RAGHAVAN [S.4] who demonstrated the perturbed angular correlation technique to be extremely powerful in this field. The experimental data collected within the following years revealed two remarkable systematic trends: the first is related to the temperature dependence of the quadrupole interaction. It was discovered at Erlangen [S. S,6] that in most cases this temperature variation follows fairly accurately a simple T 3 / 2 relation. This behaviour is found in pure metals as well as in dilute binary alloys and in many cases it holds over the entire temperature range up to the melting pOint.The second important systematics is the correlation between the ionic and the electronic field gradients [S.7,8]. This empirical result was highly unexpected in terms of the conventional ansatz of the EFG based on two independent sources, one from the lattice and the other from the conduction electrons. The "universal correlation" rather implies-besides the dependence on the geometrical array of the lattice atoms -a strong relation of the electronic gradient to the nonsphericity of the probe ion cores, which is described by the Sternheimer anti shielding factor.Stimulated by these recent experimental trends emerging from the large body of available experimental data, significant progress in the theoretical approaches can be recognized. But we are still not able to predict reliable quantitative numbers

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Quadrupole interaction studies of Hg in Sb

Cited by 17 publications

References 16 publications

Quadrupole Interaction in Metals: Nuclear Methods

Quadrupole Interaction in Metals: Nuclear Methods

199Hg M�ssbauer measurements on mercury alloys and Hg-fluorides

Electric Quadrupole Interaction in Noncubic Metals

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