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1996[X]
61Author    P. Wodniecki, B. Wodniecka, M. Marszalek, A. Z. HrynkiewiczRequires cookie*
 Title    PAC Studies of Ag-Hf Intermetallic Compounds  
 Abstract    The hyperfine quadrupole interaction of 181 Ta and 111 Cd probes in HfAg and HfiAg com-pounds was studied at 24 to 1100 K with the time -differential perturbed angular correlation (TDPAC) technique. The EFGs measured in HfAg on 181 Ta and m Cd are 1.388(5)x 10 18 VcnT 2 and 0.340(5)x 10 lx Vcm -2 , respectively. For both probe atoms a linear decrease of the EFG with temperature was observed with slopes 1.1 l(2)x 10 -4 KT 1 and 1.73(5)x 10~ 4 KT 1 for 181 Ta and "'Cd, respectively. In Hf 2 Ag, 0.469(2)x 10 18 VcnT 2 was determined on 181 Ta nuclei and 0.428(5)x 10 18 Vcm -2 on '"Cd. Also a linear EFG temperature dependence with the large slope of 2.39(6)x 10 -4 K" 1 was observed for "'Cd probes in Hf 2 Ag, while the EFG measured on l8l Ta nuclei in this compound exhibits a very weak temperature variation which can be fitted neither with a linear T nor a T ?/2 dependence. In all cases the electronic contributions to the EFG are very small indicating that these transition element systems do not obey the universal correlation between the electronic and the ionic EFG observed in numerous other systems not belonging to the transition metal series. 
  Reference    Z. Naturforsch. 51a, 437—441 (1996); received November 20 1995 
  Published    1996 
  Keywords    Hyperfine interactions, perturbed angular correlations, electric field gradient, inter-metallic compounds, Ag-Hf system 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0437.pdf 
 Identifier    ZNA-1996-51a-0437 
 Volume    51 
62Author    MichaelH. PalmerRequires cookie*
 Title    0 Nuclear Quadrupole Coupling in Molecular and Lattice Systems by ab initio Calculation of Electric Field Gradients  
 Abstract    We present ab initio Hartree-Fock calculations of electric field gradients, which are related to experimental determinations of nuclear quadrupole coupling constants. The nucleus of special interest is 17 0 but other nuclei in the molecules, especially N, 2 H and 33 S are included. The calculations were performed (a) as single molecules either at the SCF and MP2 correlated levels, (b) as clusters of molecules about a test site, or (c) as lattice calculations computed in the unit cell environment. The basis sets are triple zeta valence plus polarisation in (a). Because of limitations in exponent range in (c), the bases in both (b) and (c), where comparison was sought, are DZ at the SCF level. 
  Reference    Z. Naturforsch. 51a, 442—450 (1996); received October 20 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0442.pdf 
 Identifier    ZNA-1996-51a-0442 
 Volume    51 
63Author    MichaelH. PalmerRequires cookie*
 Title    Nuclear Quadrupole Coupling Constant assignments for a series of azoles and azines by Hartree-Fock SCF-Cluster and Lattice Calculations  
 Abstract    We present ab initio Hartree-Fock lattice calculations on a series of heterocyclic and other compounds. Some of these have previously been studied by cluster calculations with the same DZ basis sets at the SCF level. The electric field gradients at the nitrogen centres, are related to NQR experimental determinations of nuclear quadrupole coupling constants. The compounds studied include imidazole and pyrazole, 4-nitroimidazole, 4-nitropyrazole, pyrazine, and tetram-ethylpyrazine, pyridinium chloride, and N-methylpyridinium iodide, and pyridine-N-oxide. 
  Reference    Z. Naturforsch. 51a, 451—459 (1996); received January 5 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0451.pdf 
 Identifier    ZNA-1996-51a-0451 
 Volume    51 
64Author    MichaelH. Palmer, Paul SherwoodRequires cookie*
 Title    The Charge Distribution in Amides and Thioamides by Nuclear Quadrupole Coupling, Dipole Moments and Electronic Structure Calculations  
 Abstract    The nuclear quadrupole coupling constants from microwave spectroscopy (MW) and quadrupole resonance (NQR) for amides and thioamides are discussed in relation to Hartree-Fock calculations with and without Moller-Plesset correlation effects. The view that the larger dipole moments from thioamides than the corresponding amides is a function of enhanced resonance in the former is discussed and (in effect) confirmed by the present procedures. The principal mechamism seems to be the push/pull K/C effects of the N atom with respect to the CO and CS groups, with S being a better o-donor than O; however, the effect is still present with formamidine where no electronegativity effects are important, so the overall effect is the 2,1,17t-electron contribution to the allylic system from N, C, O(S). The use of localised MO's and NO's is described, and the centroid positions are discussed in relation to the polarity of the bonds. The LMO's largely truncate the contributions to each NQCC to the three attached bonds (or 2 bonds + a lone pair orbital at O or S), as is used in the Townes-Dailey procedures. More distant LMO's generally contribute < 0.05 a. u. to the EFG, simplifying the analysis. The effects of 0(or S)-protonation of urea and thiourea is discussed. 
  Reference    Z. Naturforsch. 51a, 460—478 (1996); received February 1 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0460.pdf 
 Identifier    ZNA-1996-51a-0460 
 Volume    51 
65Author    MichaelH. PalmerRequires cookie*
 Title    Quadrupole Coupling in Purines and Pyrimidines by Hartree-Fock Lattice Calculations of Electric Field Gradients  
 Abstract    We present ab initio Hartree-Fock lattice calculations on adenine, guanine and hypoxanthine, and some pyrimidines, including cytosine and uracil derivatives. The electric field gradients at the nitrogen centres are related to NQR experimental determinations of nuclear quadrupole coupling constants. The calculations were performed as lattice calculations in the unit cell environment, with 6-31G or double zeta basis sets at the SCF level. The present analysis strongly suggests that at N 3 in cytosine, N 3 in guanine are both positive, and approximately tangential to the ring at that centre. In contrast, N 7 in guanine is like most other azine-type N centres, with a largely radial direction for The 3-protonated cytosine ring has x-as the local 7r-direction. 
  Reference    Z. Naturforsch. 51a, 479—188 (1996); received January 5 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0479.pdf 
 Identifier    ZNA-1996-51a-0479 
 Volume    51 
66Author    Alfred Seeger, Jörg Ehmann, Manfred FähnleRequires cookie*
 Title    Electric Field Gradients Around Point Defects in Metals  
 Abstract    The splittings of nuclear energy levels caused by the electric field gradients acting on the quadru-pole moments of nuclei in the neighbourhood of atomic defects in cubic metals may serve as "fingerprints" providing us with a unique characterization of these defects. In favourable cases the NQDOR technique (nuclear quadrupole double resonance) permits sensitive measurements of these splittings with good resolution. The present paper outlines the status of the ab-initio calculation of electric field gradients with emphasis on the theoretical basis (density functional theory with local density approximation) and on the techniques required for handling the specific problems associated with defects. Recent work by the supercell approach on atomic defects in Al and Cu, making use either of the full-potential linearized augmented-plane-wave method or of the ab-initio pseudopo-tential method, are reported and compared with experiments. The excellent agreement between experiment and theory for the field gradients acting on the nearest-neighbour nuclei of monovacan-cies in Al demonstrates the reliability and the potential of the theory. Ab-initio electron theory; Nuclear quadru-pole double resonance; Atomic defects in Al and Cu. 
  Reference    Z. Naturforsch. 51a, 489—505 (1996); received February 3 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0489.pdf 
 Identifier    ZNA-1996-51a-0489 
 Volume    51 
67Author    K. Konzelmann, G. Majer, A. SeegerRequires cookie*
 Title    Solid Effect Between Quadrupolar Transitions in Dilute Cu-Pd Alloys  
 Abstract    The paper investigates the Dynamic Solid Effect (DSE) in Nuclear Quadrupole Double Reso-nance (NQDOR) on a system (dilute alloys of CuPd with 8, 42, 210, or 1000 at.ppm Pd) chosen for its simplicity and the possibility to test the theoretical concepts on which the experimental tech-niques (in particular the so-called Berthier-Minier technique for exhibiting the DSE) are based. NQDOR allows to observe the transitions between the Cu nuclear energy levels split by the quadrupolar interaction with the electric field gradients generated by nearby Pd atoms even in dilute alloys, in which the fraction of Cu nuclei experiencing a given field gradient is very small. The DSE permits transitions at frequencies corresponding to the sums or differences of quadrupolar level splittings at neighbouring nuclei and thus gives access to information on the spatial correlation of nuclei accessible to NQDOR studies. The DSE information is shown to be in full accord with the conclusions drawn earlier, on the basis of line-intensity arguments, on the assignment of quadrupo-lar transitions to the first four shells of Cu nuclei surrounding isolated Pd atoms but, in addition, allows to identify the low-frequency NQDOR lines associated with Cu nuclei in the fifth and sixth shells. 
  Reference    Z. Naturforsch. 51a, 506—514 (1996); received February 13 1996 
  Published    1996 
  Keywords    Nuclear quadrupole double resonance, Atomic defects in Cu, Electric field gradients, Solid effect 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0506.pdf 
 Identifier    ZNA-1996-51a-0506 
 Volume    51 
68Author    B. Hannebauer, P. C. Schmidt, R. Kniep, N. Jansen, D. Walcher, P. Gütlich, R. Gottschall, R. Schöllhorn, M. MethfesselRequires cookie*
 Title    Ab-initio Band Structure Calculations and 61 Ni-Mössbauer Studies of BaNi0 2 , BaNi0 3 and CaNiN  
 Abstract    The electron density distribution of the nickel compounds BaNi0 2 , BaNi0 3 and CaNiN has been investigated experimentally by 61 Ni Mössbauer spectroscopy and theoretically by band structure calculations using the FP-LMTO (Full Potential Linear Afuffin-71n Orbital) method. For all compounds good agreement is found between the experimental and theoretical values of the electric field gradient <f xp and q lheoT at the nickel site. BaNi0 2 contains nickel in a square-planar coordination forming puckered chains of edge-sharing Ni0 4 squares. \q\ at nickel is large: q exp = -15.7(1.5) • 10 fl Vm" 2 and q thcot -= -15.59 • 10 21 Vm" 2 . The principal axis z is perpendicular to the Ni0 4 squares. The crystal structure of BaNiO a contains face-sharing chains of NiO. octahedra. In BaNi0 3 g(Ni) is small: q" p • = ±3.6(2.0) • 10 21 Vm~ 2 and q theor = — 1.86 • 10 2 Vm -2 . Because of the small broadening of the Mössbauer resonance line the sign of q could not be determined experimentally. The nitridoniccolate CaNiN contains infinite linear chains oo [NiN 2/2 ] which run perpendicular to the c axis. Unexpectedly, |<?(Ni)| in CaNiN is small: q exp = 0.0 (2.0) • 10 Jl Vm -2 and qtheor. _ _ 3 05 . |Q2i Vm~ 2 . Again the sign of q(Ni) could not be determined experimentally. It is found theoretically that the small value of ^r (Ni) is caused by severe cancellation between a and n contributions. 
  Reference    Z. Naturforsch. 51a, 515—526 (1996); received December 27 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0515.pdf 
 Identifier    ZNA-1996-51a-0515 
 Volume    51 
69Author    K. Schwarz, H. Ripplinger, P. BlahaRequires cookie*
 Title    Electric Field Gradient Calculations of Various Borides  
 Abstract    A first-principles method for the computation of electric field gradients (EFG) is illustrated for various borides. It is based on energy band calculations using the full-potential linearized aug-mented plane wave (LAPW) method within density functional theory. From the self-consistent charge density distribution the EFG is obtained without further approximations by numerically solving Poisson's equation. The dependence of the EFG on structure, chemical composition or substitution is demonstrated for the diborides MB 2 (with M = Ti, V, Cr, Zr, Nb, Mo, and Ta), the hexaborides (CaB 6 , SrB 6 and BaB 6) and boron carbide which is closely related to a-boron. 
  Reference    Z. Naturforsch. 51a, 527—533 (1996); received October 10 1995 
  Published    1996 
  Keywords    Band-structure calculations Electric field gradient, Diborides, Hexaborides, Boron carbide 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0527.pdf 
 Identifier    ZNA-1996-51a-0527 
 Volume    51 
70Author    N. Sathyan, V. Santhanam, J. SobhanadriRequires cookie*
 Title    Conformational Analysis of Chloromethylenimine and its Hydrogen-Bonded Dimers with Water from the Study of Nuclear Quadrupole Interactions  
 Abstract    A molecular conformation study on N-Chloromethylenimine and its 1:1 dimeric form with water has been carried out using the ab-initio method at 6-31 G and 6-31 G* basis set. We consider the two most stable conformers of the N-chloromethylenimine -water binary mixture involving double hydrogen bonds. In all cases the proton affinity has been calculated. Each system considered in this work has the nuclear quadrupole interactions of the nitrogen and chlorine resonant nuclei which have been calculated and compared. It is found that the nuclear quadrupole coupling constant for the nitrogen nucleus increases in the hydrogen bonded complexes and decreases for the chlorine nucleus compared to the monomeric values. The influence of proton affinity is reflected in the nuclear quadrupole coupling constant. 
  Reference    Z. Naturforsch. 51a, 534—536 (1996); received November 20. 1995 
  Published    1996 
  Keywords    N-Chloromethylenimine, Water, Hydrogen bond Nuclear Quadrupole Coupling Con-stant, Proton Affinity, Ab-initio 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0534.pdf 
 Identifier    ZNA-1996-51a-0534 
 Volume    51 
71Author    H. M. Petrilli, M. Marszalek, H. SaitovitchRequires cookie*
 Title    Study of the EFG Trends in Zr 2 T (T = Fe, Co, Ni) Intermetallic Compounds  
 Abstract    We use the linear muffin-tin orbital formalism, in the atomic sphere approximation, to investigate the trends of the electric field gradient (EFG) at the nucleus for the non-equivalent sites in Zr 2 T (T = Fe, Co and Ni) intermetallic compounds. As all those compounds crystallize in the same C16 crystallographic structure, they offer a rare opportunity to investigate electronic structure effects coming from transition metals on the EFG at Zr site. Those results are compared with EFG values obtained from quadrupole coupling constant measurements performed with the time differential perturbed angular correlation (TDPAC) technique, using the 181 Ta probe. 
  Reference    Z. Naturforsch. 51a, 537—543 (1996); received February 13 1996 
  Published    1996 
  Keywords    Electric Field Gradient, Intermetallic Compounds, LMTO-ASA, Electronic Structure, Nuclear Quadrupole Interactions 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0537.pdf 
 Identifier    ZNA-1996-51a-0537 
 Volume    51 
72Author    G. V. Dolgushin, I. M. Lazarev, P. A. Nikitin, L. I. LarinaRequires cookie*
 Title    C1 NQR of the N-Cl Bond and the Modified Townes-Daily Theory  
 Abstract    The modified Townes-Daily equation is shown to be better than the original one for frequencies of compounds having N-Cl bonds. Of the three semi-empirical methods AM 1, MNDO, PM 3, the first is preferable. The asymmetry parameters for the same compounds have been evaluated. The 35 C1 NQR frequencies of two tautomers of N-chlorobenzotriazole are compared. 
  Reference    Z. Naturforsch. 51a, 544—548 (1996); received October 13 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0544.pdf 
 Identifier    ZNA-1996-51a-0544 
 Volume    51 
73Author    ValentinP. Feshin, Mikhail Yu, KonshinRequires cookie*
 Title    Ab initio and MNDO Calculations of the 35 C1 NQR Parameters of Some Organic and Inorganic Molecules  
 Abstract    The results of ab initio and MNDO calculations of the Cl 2 C = CHOCH 3 , XCOC1 (X = CH 3 , OCH 3 and COC1), 4-ClC 6 H 4 CH 2 Cl, (CNC1) 3 and PC1 5 with total optimization of their geometry are presented. The ab initio calculations were executed using Hartree-Fock theory and the split valence basis set 6-31G* (RHF/6-31 G*//RHF/6-31G*). Using the calculated p-orbital populations of the CI atoms in these molecules the 35 C1 NQR frequencies and asymmetry parameters of the EFG at the 35 C1 nuclei have been determined. When the populations of the less diffuse components of orbitals in the split valence basis set are used the calculated and experimenal v and rj values are in good agreement. Linear correlations between these calculated and corresponding experimental v and rj values are obtained. The causes of the nonconformity of the earlier calculated v and t] values and their experimental ones are analysed. Key words: Ab initio calculations, p-orbital populations, 35 C1 NQR frequency, asymmetry parameter. 
  Reference    Z. Naturforsch. 51a, 549—553 (1996); received October 10 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0549.pdf 
 Identifier    ZNA-1996-51a-0549 
 Volume    51 
74Author    M. J. PonnambalamRequires cookie*
 Title    F-Tensor Coefficients in Electric Field Gradient Calculations for Non-Coulombic Potentials  
 Abstract    The F-tensor coefficients are useful in evaluating the stress-induced electric field gradients in cubic crystals. These coefficients are derived for the non-Coulombic inter-atomic potentials Gr~" and Ge' br . Interesting differences are pointed out between these results and those for Coulombic potentials. 
  Reference    Z. Naturforsch. 51a, 554—556 (1996); received February 13 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0554.pdf 
 Identifier    ZNA-1996-51a-0554 
 Volume    51 
75Author    F. Hagelberg, T. P. Das, K. G. WeilRequires cookie*
 Title    Electric Field Gradients for Small Antimony Based Zintl Clusters from Hartree-Fock Investigations  
 Abstract    Electric Field Gradient (EFG) calculations have been carried out for Antimony based clusters with 20 and with 22 valence electrons. It is shown that EFGs are very sensitive to structural changes of the clusters under study. This feature can be used to demonstrate the validity of the Zintl-Klemm-Busmann principle for these systems through EFG determinations. 
  Reference    Z. Naturforsch. 51a, 557—559 (1996); received February 3 1996 
  Published    1996 
  Keywords    Ab Initio Theory, Atomic Clusters, Antimony Molecules, Electric Field Gradients, Zintl Clusters 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0557.pdf 
 Identifier    ZNA-1996-51a-0557 
 Volume    51 
76Author    StadeS. Nunes, S. Sulaiman, N. Sahoo, T. P. Das, M. Frank, W. Kreische, K. B. NielsenRequires cookie*
 Title    Study of the Location of Implanted Fluorine Atoms in Silicon and Germanium through Their Nuclear Quadrupole Interactions  
 Abstract    Time Differential Perturbed Angular Distribution (TDPAD) measurements of the nuclear quadrupole hyperfine parameters for 19 F* implanted into amorphous, polycrystalline and crys-talline silicon and germanium are reported and reviewed. Two signals are observed in the crystalline materials (« 35 and 23 MHz in silicon, % 33 and 27 MHz in germanium) while only one is detected in the amorphous and polycrystalline samples (ä22 MHz in silicon, «27 in germanium). Impurity sites in these materials were modeled using a Hartree-Fock cluster procedure. The Intrabond, Antibond, and Substitutional sites in the bulk were studied in both silicon and germanium. The ATOP and Intrabond Surface sites were also studied in silicon and the results extended to germa-nium. Lattice relaxation effects were incorporated by employing a geometry optimization method to obtain minimum energy configurations for the clusters modelling each site. The electronic wave functions were obtained for each optimized cluster by applying Unresctricted Hartree-Fock theory, and these wave functions were used to calculate the nuclear quadrupole hyperfine parameters at the site of the fluorine nucleus. Comparison of the theoretical hyperfine parameters to the experimental values indicates that 19 F* located in the Intrabond and Intrabond surface sites could readily explain the higher frequency signal that has been observed. 19 F* in the Antibond and the surface ATOP sites yield hyperfine parameters consistent with the low frequency signal observed in the crystalline materials and the single signal observed in the amorphous (or polycrystalline) materials. Examina-tion of these two sites, in view of other available experimental evidence including the temperature dependence of the TDPAD signals, leads to the conclusion that the lower frequency signal is due to 19 F* implants which have come to rest at the site of dangling bonds in the bulk. These dangling bonds are created as a result of damage generated in the individual collision cascades during the implantation process. 
  Reference    Z. Naturforsch. 51a, 560—564 (1996); received December 12 1995 
  Published    1996 
  Keywords    Semiconductors, Impurities, Electronic structure, Hartree-Fock, Electric field gradient 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0560.pdf 
 Identifier    ZNA-1996-51a-0560 
 Volume    51 
77Author    G. Gowri, Tina Briere, Sudha Srinivas, Hwa-Suck Cho, T. P. Das, M. Frank, W. Kreische, K.V S Rama RaoRequires cookie*
 Title    Theory of Nuclear Quadrupole Interactions in Solid Fluoromethanes with Implanted l9 F* Nuclei. Coupling of HF* and Host Molecule  
 Abstract    The Quadrupole Coupling Constant e 2 qQ and Asymmetry Parameter rj of fluorine for fluorine-substitute methane compounds are calculated using the Hartree-Fock Roothaan procedure. Our results are compared with experimental data from measurements by the Time Differential Perturbed Angular Distribution (TDPAD) technique using excited 19 F* (spin 5/2) nuclei. The theoretical e 2 qQ's for the 19 F* nuclei in the fluoromethanes are in good agreement with experimental results. For CH 2 F 2 and CHC1F 2 molecules, where finite rj are expected from symmetry considerations, our results for ri are small, 0.12 and 0.05 respectively, in agreement with experimental observation. Besides the F* coupling constants associated with the C-F bonds in fluoromethanes, additional interesting NQI parameters, close to those in solid hydrogen fluoride, are observed in the TDPAD measurements. It is demonstrated through investigations of the total energies and electric field gradients that these additional NQI parameters for the fluoromethanes can be explained by a HF* molecule hydrogen-bonded through the hydrogen to a fluorine atom in the host molecular systems. This complexing of an ionic molecule to the host molecules in organic solids containing strongly electronegative atoms is expected to be a general feature in both implantation and conventional techniques. 
  Reference    Z. Naturforsch. 51a, 565—571 (1996); received March 8 1996 
  Published    1996 
  Keywords    Nuclear Quadrupole Interaction, 19 F* (nuclear excited state), Fluoromethane, Hartree-Fock Calculation, Hydrogen Bonding 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0565.pdf 
 Identifier    ZNA-1996-51a-0565 
 Volume    51 
78Author    P. BoolchandRequires cookie*
 Title    Nuclear Quadrupole Interactions as a Probe of Glass Molecular Structure  
 Abstract    125 Te absorption and 129 I emission Mössbauer spectroscopies have proved to be the methods of choice to probe chalcogen chemical order in condensed matter using nuclear quadrupole interac-tions. In chalcogenide glasses, the technique has been unusually rewarding in decoding both the elements of local atomic structures and those of the medium-range atomic structures. 
  Reference    Z. Naturforsch. 51a, 572—584 (1996); received October 20 1995 
  Published    1996 
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 Identifier    ZNA-1996-51a-0572 
 Volume    51 
79Author    W. Müller-WarmuthRequires cookie*
 Title    The Structure of Glasses Studied by MAS-NMR Spectroscopy of Quadrupolar Nuclei *-Al 2 0 3 -Si0 2 , B 2 0 3 -A1 2 0 3 -P 2 0 5 , Na 2 0-B 2 0 3 -Si0 2 and Na 2 0-B 2 0 3 -Al 2 0 3  
 Abstract    High-resolution solid state NMR spectroscopy of quadrupolar nuclei (preferentially n B and 27 A1) has been employed to study the microstructure of glasses. Importance has been attached to the extraction of the fundamental NMR parameters like chemical shift, quadrupole coupling con-stant etc., from the spectra, first of all by applying satellite transition spectroscopy. Exemplary results are represented for ternary oxide glass systems such as K 2 0 
  Reference    Z. Naturforsch. 51a, 585—590 (1996); received October 10 1995 
  Published    1996 
  Keywords    MAS-NMR Spectroscopy, Quadrupole Satellite Transitions, 27 A1 NMR, n B NMR Glasses (Microstructure) 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0585.pdf 
 Identifier    ZNA-1996-51a-0585 
 Volume    51 
80Author    Ho Sung, ChohRequires cookie*
 Title    Magnetic Resonances of 5l V, 209 Bi, Mn 2 + , and Fe 3 + in BiV0 4 Single Crystals  
 Abstract    Nuclear magnetic resonance (NMR) of 51 V and 209 Bi, and electron paramagnetic resonance (EPR) of Mn 2 and Fe 3+ impurities in ferroelastic BiV0 4 single crystals are reviewed. The nuclear quadrupole parameters and principal axes of the two host nuclei, 51 V and 209 Bi, and the second-or-der zero field splitting tensor of the isoelectronic 3d 5 ions, Mn 2 + and Fe 3 + , in Bi V0 4 are determined for the first time. Temperature dependence studies on 51 V NMR and Mn 2+ EPR confirmed that this crystal undergoes a second order phase transition. The substitutional sites of Mn 2+ and Fe 3 + in BiV0 4 are Bi 3 and V 5 + , respectively. 
  Reference    Z. Naturforsch. 51a, 591—602 (1996); received February 3 1996 
  Published    1996 
  Keywords    NMR, EPR, Quadrupole parameters Zero field splittings, Substitutional sites 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0591.pdf 
 Identifier    ZNA-1996-51a-0591 
 Volume    51 
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