Go toArchive
Browse byFacets
Bookbag ( 0 )
'Electric Field Gradient' in keywords
Results  21 Items
Sorted by   
Section
Publication Year
2000 (4)
1999 (1)
1998 (2)
1996 (7)
1994 (3)
1993 (1)
1992 (2)
1990 (1)
1Author    R. Julian, C. Brown, MeganE. Shortreed, AndrewJ. Szabo, BrianM. Powell, StephenN. StuartRequires cookie*
 Title    NQR and Neutron Diffraction in Scheelites  
 Abstract    Measurements of the spin-lattice relaxation time for rhenium in KRe04 and NH4Re04 are reported; relaxation rates are extremely fast due to the large quadrupole moment of Re. Calculations of the electric field gradient in KRe04 show that the EFG is a very sensitive function of the orientation of the anion in the unit cell as well as of the unit cell dimensions, and that geometrical effects make a major contribution to the temperature dependence. Neutron diffraction in these two salts has been employed to determine the temperature dependence of structural parameters over a wide range of temperature, and preliminary results are reported. 
  Reference    Z. Naturforsch. 47a, 308—312 (1992); received August 4 1991 
  Published    1992 
  Keywords    NQR, Relaxation, Electric field gradient, Neutron diffraction 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0308.pdf 
 Identifier    ZNA-1992-47a-0308 
 Volume    47 
2Author    DesmondC. CookRequires cookie*
 Title    Measurement of Nuclear Quadrupole Interactions using Mössbauer Spectroscopy  
 Abstract    Mössbauer spectroscopy is a useful probe for investigating nuclear quadrupole interactions. It enables the magnitude, sign and asymmetry of the electric quadrupole coupling constant to be determined. It is especially important for its ability to measure these parameters for excited nuclear states. The Mössbauer effect is used to measure excited state quadrupole moments in materials whose electric field gradient (EFG) is known. More commonly however, it is used to determine the EFG from which atomic bonding and electronic structure are determined. The technique also allows temperature dependent orientation of sublattice magnetization to be measured using the direction of the electric quadrupole coupling as a reference. 
  Reference    Z. Naturforsch. 51a, 368—372 (1996); received November 20 1995 
  Published    1996 
  Keywords    Mössbauer Effect, Electric Field Gradient, Quadrupole Interaction 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0368.pdf 
 Identifier    ZNA-1996-51a-0368 
 Volume    51 
3Author    Lars Hemmingsen, Ulf Ryde, Rogert BauerRequires cookie*
 Title    Nuclear Quadrupole Interactions in Cadmium Complexes: Semiempirical and ab initio Calculations  
 Abstract    Semiempirical calculations, based on the so-called angular overlap model, have been compared with ab initio methods (MP2) for the calculation of nuclear quadrupole interactions (NQPs) in cadmium complexes with biologically relevant ligands (H2O, OH -, cysteinate, carboxylate, and imidazole). The assumptions on which the semiempirical model is based have been tested and the comparison indicates that: 1) A change in the Cd-ligand bond length by 0.1 A may change the electric field gradient (EFG) by about 0.2 a. u.. A simple scheme to incorporate such effects in the semiempirical method is suggested. 2) The effect of ligand-ligand interactions is up to about 0.2 a. u. for the largest diagonal element of the EFG tensor for the tested complexes, and such effects can significantly influence the so-called asymmetry parameter. 3) The position of non-coordinating atoms on the ligands can in some cases (e. g. the hydrogen atoms of water) significantly influence the EFG. The combined effect of non-coordinating atoms and ligand-ligand interactions may cause deviations of up to 0.35 a.u. between ab initio and the semiempirical calculations. 4) In the semiempirical model each ligand is characterised by one parameter, the so-called partial nuclear quadrupole interaction. This parameter has been evaluated by ab initio calculations, and agreement was found within about 0.2 a. u. (« 40 Mrad/s) for all ligands except imidazole. 5) A change in the coordination number from 2 to 6 may change the partial NQI by about 0.3 a. u. 
  Reference    Z. Naturforsch. 54a, 422—430 (1999); received March 29 1999 
  Published    1999 
  Keywords    Electric Field Gradient, Angular Overlap Model, Ligand Additivity 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0422.pdf 
 Identifier    ZNA-1999-54a-0422 
 Volume    54 
4Author    David Stephenson, JohnA S SmithRequires cookie*
 Title    The Zeeman Effect in Quadrupole Double Resonance Spectra: Dependence of the Line Shapes on the Orientation of the Electric Field Gradient Tensor  
 Abstract    The solid effect spectrum of 1,4-dichlorobenzene was recorded at magnetic field strengths in excess of 50 G; at these field strengths Zeeman structure is seen on the 35C1 resonance. Unlike in single resonance experiments, peaks are asymmetric, and the high frequency and low frequency solid effect peaks have not the same shape. Computer calculation o f the solid effect spectrum gives peaks which show the same asymmetry as the experimental spectrum. The simulated line shapes are found to depend on the direction the principal com ponents o f the electric field gradient in the crystal framework and indicate that qyy lies in the plane o f the benzene ring. 
  Reference    Z. Naturforsch. 49a, 351 (1994); received July 23 1993 
  Published    1994 
  Keywords    35C1 quadrupole resonance, Zeeman effect, D ouble resonance, Electric field gradient 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0351.pdf 
 Identifier    ZNA-1994-49a-0351 
 Volume    49 
5Author    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 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0560.pdf 
 Identifier    ZNA-1996-51a-0560 
 Volume    51 
6Author    A. C. Junqueira, A. W. Carbonari, J.Mestnik Filho, R. N. SaxenaRequires cookie*
 Title    Electric Field Gradient at Nb Site in the Intermetallic Compounds Nb 3 X (X = AI, In, Si, Ge, Sn) Measured by PAC  
 Abstract    The electric field gradient (efg) at the Nb site in the intermetallic compounds Nb 3 X (X = Al, In, Si, Ge, Sn) was measured by the Perturbed Angular Correlation (PAC) method using the well-known gamma-gamma cascade of 133 -482 keV in lxl Ta from the ß~ decay of 1K1 Hf, substituting approximately 0.1 atom percent of Nb. The PAC results show that V zz drops by nearly 40% when X changes from Al to In, and by about 25% when X changes from Si to Ge and Sn. This behavior is most probably related to the change in the degree of sp hybridization in these compounds. The V zz values of the studied compounds do not follow the well known universal correlation for the efg's in non-cubic metals but the observed trend is well reproduced by results of ab-initio electronic structure calculations. In the case of Nb 3 Al a linear temperature dependence of the quadrupole frequencies was observed in the temperature range of 6.5 to 1210 K. 
  Reference    Z. Naturforsch. 55a, 41—14 (2000); received August 25 1999 
  Published    2000 
  Keywords    Electric Field Gradient, PAC Measurements, Nb-based Alloys, Quadrupole Interactions 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0041.pdf 
 Identifier    ZNA-2000-55a-0041 
 Volume    55 
7Author    Hirokazu Nakayama, Kazuya Saito, Michihiko KishitaRequires cookie*
 Title    Improvement of Bertaut's Method for Calculating Electric Field Gradient  
 Abstract    Bertaut's method for calculating the electric field and its gradient is analyzed. The formula for the electric field is always valid, whereas that for the electric field gradient holds only for an infinitely large unit cell. We present a practical method to use the formulae. 
  Reference    Z. Naturforsch. 45a, 375—379 (1990); received August 23 1989 in revised version January 5 1990 
  Published    1990 
  Keywords    Electric field gradient, Electrostatic potential, Electrostatic field, Lattice sum, Bertaut's method 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-0375.pdf 
 Identifier    ZNA-1990-45a-0375 
 Volume    45 
8Author    Karlheinz Schwarz, Peter BlahaRequires cookie*
 Title    Ab initio Calculations of the Electric Field Gradients in Solids in Relation to the Charge Distribution  
 Abstract    A first principles method for the computation of electric field gradients (EFGs) is illustrated for various solids. This scheme is based on self-consistent energy band-structure calculations by the full potential linearized augmented plan wave (FLAPW) method which provides the electronic charge density including all polarization effects. By numerically solving Poisson's equation we obtain the Coulomb potential in a form which allows to compute the EFG directly. Our method is demon-strated for insulators (Cu20), metals (hcp-Zn), supercondutors (YBa2Cu3Ö7) and molecular crystals (Cl2, Br2, I2). 
  Reference    Z. Naturforsch. 47a, 197—202 (1992); received August 3 1991 
  Published    1992 
  Keywords    Band-structure calculation, Electric field gradient, Nuclear quadrupole interaction, Molecular crystals, High-Tc superconductors 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0197.pdf 
 Identifier    ZNA-1992-47a-0197 
 Volume    47 
9Author    Jiahu Wang, VedeneH. SmithRequires cookie*
 Title    Ab initio Study of the Electric Field Gradients in SC1 2  
 Abstract    The electric field gradients (EFG) in SC1 2 have been computed with both self-consistent-field (SCF) and configuration-interaction (CI) methods. The predicted EFG, along with the nuclear quadrupole moment Q N of 35 C1 and 37 C1 from other sources, allows us to compare theoretical quadrupole coupling constants with new experimental results. The best values obtained agree with the experiment within 3%. It has been found that the principal axis of the coupling tensor does not coincide with the S-Cl internuclear axis, and the tilt angle has been predicted close to that from experiment. 
  Reference    Z. Naturforsch. 48a, 699—702 (1993); received March 13 1993 
  Published    1993 
  Keywords    Electric field gradient, Nuclear quadrupole coupling constant, SC1 2, ab initio method, Bent chemical bond 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0699.pdf 
 Identifier    ZNA-1993-48a-0699 
 Volume    48 
10Author    P. Blaha, K. Schwarz, P. Dufek, G. Vielsack, W. WeberRequires cookie*
 Title    The Breathing Mode of B a B i0 3: Electric Field Gradient and Total Energy Calculations  
 Abstract    We present ab initio full-potential linearized augmented plane wave (LAPW) band structure calculations for BaBiOa. We focus on total energies and electric field gradients at the oxygen site and present results for the breathing mode in the experimentally observed cubic and monoclinic struc­ tures of doped and undoped Baj _JC K xB i0 3. 
  Reference    Z. Naturforsch. 49a, 129—132 (1994); received 
  Published    1994 
  Keywords    B aB i03, Total energy, Electric field gradient, Energy band structure, Breathing mode 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0129.pdf 
 Identifier    ZNA-1994-49a-0129 
 Volume    49 
11Author    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 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0437.pdf 
 Identifier    ZNA-1996-51a-0437 
 Volume    51 
12Author    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 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0506.pdf 
 Identifier    ZNA-1996-51a-0506 
 Volume    51 
13Author    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 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0537.pdf 
 Identifier    ZNA-1996-51a-0537 
 Volume    51 
14Author    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 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0557.pdf 
 Identifier    ZNA-1996-51a-0557 
 Volume    51 
15Author    H. Honda, M. Kenmotsu, N. Onoda-Yamamuro, H. Ohki, S. Ishimaru, R. Ikeda, Y. FurukawaRequires cookie*
 Title    N and 133 Cs Solid NMR Studies on Ionic Dynamics in Plastic CsN0 2  
 Abstract    The temperature dependence of the 15 N and 133 Cs NMR spin-lattice relaxation times, the 15 N spin-spin relaxation time, and the 1S N and 133 Cs spectra of CsNOi was observed in the plastic phase (209.2 < T < 673 K (m. p.)) and the low-temperature phase (Phase II). In Phase II we found the N07 180°-flip, which could be attributed to the anomalous increase of the heat capacity curve, and determined the activation energy of this motion to be 8.7-11.7 kJ mol -1 . The l5 N and 133 Cs spectra in this phase are inconsistent with the reported crystal structure R3m and can be explained by lower crystal symmetry. In the plastic phase we detected a new anionic motion with 11 kJ mol -1 , an isotropic N07 reorientation with 8.5-9 kJ mol -1 , and ionic self-diffusion with 47 kJ mol . The presence of ionic self-diffusion was confirmed by measuring the electrical conductivity. 
  Reference    Z. Naturforsch. 51a, 761—768 (1996); received October 24 1995 
  Published    1996 
  Keywords    |S N and 133 Cs Solid NMR, Plastic crystal Phase transition Chemical shift anisotropy, Electric field gradient 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0761.pdf 
 Identifier    ZNA-1996-51a-0761 
 Volume    51 
16Author    K. Sato, H. Akai, T. MinamisonoRequires cookie*
 Title    Ab initio Calculations of Electric Field Gradients for Transition Metal Impurities in TiO z  
 Abstract    We present ab initio calculations of EFGs at impurities in a Ti0 2 crystal. They are directly calculated from the self consistent charge distribution which is determined by the KKR method within the muffin-tin approximation and based on the local density approximation. Impurities in the crystal are simulated by the super-cell method. Considering the charge state of Sc, Ti, Nb, Cd, Ta impurities in the Ti0 2 , the experimental values were well reproduced. The electronic structure of these impurities is discussed by analyzing the calculated density of states. 
  Reference    Z. Naturforsch. 53a, 396—403 (1998); received October 31 1997 
  Published    1998 
  Keywords    Ti0 2, Electric Field Gradient, Transition Metal Impurity, Band-Structure, Charge State 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/53/ZNA-1998-53a-0396.pdf 
 Identifier    ZNA-1998-53a-0396 
 Volume    53 
17Author    K. Sato, S. Takeda, S. Fukuda, T. Minamisono, M. Tanigaki, T. Miyake, Y. Maruyama, K. Matsuta, M. Fukuda, Y. NojiriRequires cookie*
 Title    FT-NMR Detection of 45 Sc, 49 Ti and 93 Nb in Ti0 2 Single Crystal  
 Abstract    In order to determine the electric quadrupole moment of the short-lived Remitter 41 Sc from the quad-rupole coupling constant in Ti0 2 , we measured the field gradient by detecting the Fourier-Transformed-NMR of stable isotope 45 Sc doped in TiO->. Also, in order to study the electronic structure of impurities systematically, EFGs were measured for * 5 Sc, 49 Ti and 93 Nb in a Ti0 2 single crystal. 
  Reference    Z. Naturforsch. 53a, 549—551 (1998); received December 31 1997 
  Published    1998 
  Keywords    Ti0 2, 41 Sc, Quadrupole Moment, Transition Metal Impurity, Electric Field Gradient 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/53/ZNA-1998-53a-0549.pdf 
 Identifier    ZNA-1998-53a-0549 
 Volume    53 
18Author    P. F. Meier, T. A. Claxton, P. Hüsser, S. Plibersek, E. P. StollRequires cookie*
 Title    Cluster Calculations of Hyperfine Interactions in Superconducting Copper Compounds  
 Abstract    This paper discusses first-principles cluster investigations on the electronic structure of YBa2Cu3Ü7 and La2CuC>4 performed at the University of Zürich. In particular, electric field gradients have been calculated at the copper sites and their dependence on applying uniaxial strain is studied. Magnetic hyperfine interactions have been evaluated from spin-polarized calculations, and the transfer of spin density from neighboring copper ions is explained. An interpretation is given of the nuclear quadrupole resonance spectra in doped La2CuC>4. 
  Reference    Z. Naturforsch. 55a, 247—255 (2000); received August 26 1999 
  Published    2000 
  Keywords    Cluster Calculations, Electric Field Gradients, High-Temperature Superconductors, Hyperfine Fields, Nuclear Quadrupole Resonance 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0247.pdf 
 Identifier    ZNA-2000-55a-0247 
 Volume    55 
19Author    LeonardoA. Errico, Gabriel Fabricius, Mario RenteríaRequires cookie*
 Title    FP-LAPW Study of the EFG at Impurity Sites in Oxides: Cd in Rutile TiO 2  
 Abstract    We report here first-principles determination of the electric-field gradient (EFG) tensor at the Cd im-purity located at cation sites in rutile Ti0 2 . As far as we know, these represent the first ab initio calcu-lations at impurity sites with the FP-LAPW method in oxide systems. We used super-cells to simulate the diluted impurity in the crystal. The free-relaxation process performed in our study shows that the changes in distances of the oxygen nearest-neighbours to the impurity are not isotropic as was suppo-sed in a previous study within the muffin-tin approximation. Our prediction for the EFG component of major absolute value agrees well with the experiment and is opposite in sign and direction if isotropic relaxations are assumed. Our value of the asymmetry parameter r\ also compares very well with the ex-perimental value. 
  Reference    Z. Naturforsch. 55a, 267—270 (2000); received August 26 1999 
  Published    2000 
  Keywords    Electric-Field Gradient, FP-LAPW, Impurity-Induced Lattice Relaxation, Electronic Struc-ture, Ti0 2 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0267.pdf 
 Identifier    ZNA-2000-55a-0267 
 Volume    55 
20Author    G. Sulzer, B. Itterm, E. Diehl, B. Fischer, H.-P Frank, E. Jäger, W. Seelinger, H.-J Stockmann, H. AckermannRequires cookie*
 Title    Temperature Dependence of Impurity Induced EFG's in Extremely Diluted CuB  
 Abstract    The temperature dependence of impurity induced EFG 's around implanted 12B ions in Cu was measured for two lattice locations using the ß-N M R method. The induced EFG at the nearest neighbouring host atoms decreases with increasing temperature for the case of 12B stopped on interstitial sites, whereas the opposite temperature behaviour was found if 12B is situated in substi­ tutional sites. 
  Reference    Z. Naturforsch. 49a, 354 (1994); received July 23 1993 
  Published    1994 
  Keywords    N M R, ß radiation detected, Cross relaxation, Electric field gradient, Temperature dependence o f EFG, Impurity induced EFG 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0354.pdf 
 Identifier    ZNA-1994-49a-0354 
 Volume    49 
1
2
Next