NUCLEAR ELECTRIC QUADRUPOLE INTERACTION IN SINGLE CRYSTALS

1952 ◽  
Vol 30 (3) ◽  
pp. 270-289 ◽  
Author(s):  
G. M. Volkoff ◽  
H. E. Petch ◽  
D. W. L. Smellie
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Electric Quadrupole ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Gradient Tensor ◽  
Absolute Value ◽  
Principal Axes ◽  
Quadrupole Coupling

Pound's theory of the dependence of electric quadrupole splitting of nuclear magnetic resonance absorption lines in a single crystal on the orientation of the crystal in an external magnetic field is extended to cover the case of a crystal with nonaxially symmetric electric field gradient at the site of the nuclei being investigated. It is shown that an experimental study of the angular dependence of this splitting for three independent rotations of the crystal about any three mutually perpendicular axes will yield complete information about the orientation of the principal axes and the degree of axial asymmetry of the electric field gradient tensor at the site of the nuclei, and also will give the absolute value of the quadrupole coupling constant for those nuclei.The authors' experiments on the splitting of the Li7 absorption lines in a single crystal of LiAl(SiO3)2 (spodumene) are described and are used to illustrate the theory. The absolute value of the quadrupole coupling constant for the Li7 nuclei in spodumene is found to be [Formula: see text]. per sec. The axial asymmetry parameter of the field gradient tensor at the site of the Li nuclei is found to be η≡(ϕxx−ϕvv)ϕzz=0.79 ± 0.01. One of the principal axes of this tensor (the y axis corresponding to the eigenvalue of intermediate magnitude) is experimentally found to coincide with the b crystallographic axis of monoclinic spodumene as required by the known symmetry of the crystal. The other two principal axes are in the ac plane, the z axis (corresponding to the eigenvalue ϕzz of greatest magnitude) lying between the a and c axes at an angle of 48° ± 2° with the c axis.

Hyperfine Interaction Induced K-type Doubling in the mmw Spectrum of HS33SH

1995 ◽  
Vol 50 (12) ◽  
pp. 1191-1198 ◽  
Author(s):  
Axel H. Saleck ◽  
Gisbert Winnewisser
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Hyperfine Interactions ◽  
Electric Quadrupole ◽  
Rotational Spectrum ◽  
Hyperfine Parameters ◽  
Gradient Tensor ◽  
Principal Axes ◽  
Good Agreement

Abstract The rotational spectrum of the disulfane isotopomer HS33SH has been recorded and assigned between 70 and 300 GHz. In the analysis, rotational constants and 33S hyperfine parameters are derived, the latter accounting for nuclear electric quadrupole as well as nuclear spin -rotation hyperfine interactions. The quadrupole constants are in qualitative agreement with a published ab-initio calculation. The electric field gradient principal axes are considerably rotated against the principal inertial axes, giving rise to off-diagonal elements in the electric field gradient tensor. In combination with the very small inertial asymmetry of the molecule, this causes the A'-doubling in the lowest rotational levels to be dominated by the hyperfine structure rather than the inertial asymmetry contributions. By diagonalization of the quadrupole tensor, an estimate for the dihedral angle (η≈94°) can be obtained, in good agreement with a previous value.

AN INVESTIGATION OF THE NUCLEAR RESONANCE ABSORPTION SPECTRUM OF Al27 IN A SINGLE CRYSTAL OF EUCLASE

1955 ◽  
Vol 33 (6) ◽  
pp. 286-297 ◽  
Author(s):  
R. G. Eades
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Field Gradient ◽  
Resonance Spectrum ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Theoretical Dependence ◽  
Absolute Value ◽  
Principal Axes ◽  
Quadrupole Coupling

The nuclear magnetic resonance spectrum of Al27 in a single crystal of HBeAlSiO5 (euclase) in an external magnetic field of 7000 gauss is described. The Al27 nuclei are found to occupy two kinds of lattice sites which differ from each other only in the orientation of the principal axes of the electric field gradient tensors whose eigenvalues are all distinct, but identical at both sites. The absolute value of the quadrupole coupling constant for both groups of Al27 nuclei is found to be 5173 ± 10 kc./sec. and the axial asymmetry parameter of the field gradient tensors at both the lattice positions is 0.698 ± 0.009. The two sets of principal axes are reflections of each other in the (010) plane which is consistent with the symmetry of the proposed crystal structure. The theoretical dependence of the spectrum line frequencies on the applied magnetic field is given for one group of Al27 nuclei and for one orientation of the crystal in fields up to 2000 gauss; the feasibility of checking this experimentally is discussed.

Über die chemische Bindung in Gold(I)-jodid

1966 ◽  
Vol 21 (11) ◽  
pp. 1025-1027 ◽  
Author(s):  
Paul Machmer
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Quadrupole Coupling ◽  
Constant E

The molecular electric field gradient (e qzz)610 at the nucleus of the gold isotope 197 is 42,7 · 1015 esu cm-3 according to our calculations. This value was used in calculating the quadrupole coupling constant in AuI and agreement is found with the experimental quadrupole coupling constant (e2 Q qzz)/h=508.296 MHz, if 50% s2-hybridisation and 21% ionicity are attributed to the gold-iodine bond. The ionicity in AuI is perhaps greater than in AuCl, as is indicated by the lower quadrupole coupling constant of Au197 in Aul.( (e2 Q qzz) /h=508,296 MHz in AuI, 514,150 MHz in AuCl 1.) This result is discussed with respect to the Townes-Dailey rule

scholarly journals Hyperfine Structure in the Microwave Spectrum of Water

1957 ◽  
Vol 10 (2) ◽  
pp. 276 ◽  
Author(s):  
DW Posener
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Hyperfine Structure ◽  
Field Gradient ◽  
Quadrupole Coupling Constant ◽  
Microwave Spectrum ◽  
Coupling Constant ◽  
Quadrupole Coupling

Measurement of hyperfine structure in the microwave spectrum of D2O gives (eqQ)OD= + 353 � 4 kc/s for the quadrupole coupling constant of the deuteron in the direction of the OD bond, and the corresponding electric field gradient is .

Electric Quadrupole Moment of the 14N Nucleus Determined by ab initio Cl Calculation on NH3

1986 ◽  
Vol 41 (1-2) ◽  
pp. 163-165 ◽  
Author(s):  
Tae-Kyu Ha
Keyword(s):  
Electric Field Gradient ◽  
Ab Initio ◽  
Electric Quadrupole ◽  
Quadrupole Coupling Constant ◽  
Basis Set ◽  
Electric Quadrupole Moment ◽  
Coupling Constant ◽  
Hartree Fock ◽  
Quadrupole Coupling ◽  
Constant E

Based on the calculated electric field gradient (q) from ab initio Cl wavefunctions with largebasis set (including ƒ functions on N and d functions on H) and the experimental nuclearquadrupole coupling constant (e Q q) for nitrogen in NH3, an improved value o f the quadrupole moment of 14N is proposed as Q (14N ) = 2.08 x 10-26cm2. The value calculated using a wavefunctionnear the Hartree-Fock limit enlarged ≈ 10% by the Cl treatment.

The Electric Field Gradient at the Site of the Halogen Ion and Structure of Amino Acid Hydrobromides and Hydroiodides

1992 ◽  
Vol 47 (7-8) ◽  
pp. 887-917
Author(s):  
Armin Kehrer ◽  
Shi-qi Dou ◽  
Alarieh Weiss
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Room Temperature ◽  
Low Frequency ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Resonance Frequencies ◽  
Quadrupole Coupling ◽  
Frequency Coupling

Abstract The 79,81Br and 127I NQR spectra of several hydrobromides, respectively hydroiodides, of amino acides and dipeptides were studied, mostly as functions of temperature in the range 77 < T/K <420. The investigated compounds are: L-Arg • HBr • H2O, L-Cys • HBr • H2O , L - Cys - S - S - L - Cys • 2HBr, ethanolamine • HBr, L-Glu • HBr, L-His • HBr, L-His • 2HBr, L-Ile HBr • H2O , Sar • HBr, (Sar)2 • HBr, L-Val • HBr • H2O , Gly • LiBr, Gly-Gly • LiBr, ethanolamine HI, Sar • HI, (Sar)2 • HI, (Gly)2 • HI, (L-Val)2 • HI, Gly-L-Leu • HI • H2O . A phase transition with hysteresis was observed for L-Val • HBr • H2O (Tc.up = 318 K, Tc.down = 242 K). Two solid phases of Sar • HI have been studied by NQR, one crystallized from melt, the other one from aqueous solution. For three of the title compounds the crystal structure was determined at room temperature: L-His - 2HBr, P212121 , Z = 4, aj pm = 1652, b/pm = 916, c/pm = 721; L-Cys HBr H2O , P212121 , Z = 4, a/pm = 1955, b/pm = 746, c/pm = 550; Gly-L-Leu • HI • H2O , P2X, Z = 2, a / p m = 1289, b/pm = 914, c/pm = 615, ß/° = 99.In most cases the halogen ion in the studied hydrohalides is polycoordinated by hydrogen bonds of the type N - H • • • X⊖ and O - H • • • X⊖ , X = Br, I. The NQR frequencies and, for iodine, the nuclear quadrupole coupling constants depend on this coordination. A low frequency (coupling constant) region is found for pure N - H • • • X⊖ coordination. Replacing one N - H • • • X⊖ bond by O - H • • • X⊖ rises the electric field gradient, EFG, respectively the resonance frequencies. The dependence of the EFG on the hydrogen bond coordination N - H • • • X⊖ plus O - H • • • X⊖ is discussed for the title compounds including information from literature

Criteria for assessing theoretically derived electric field gradient tensor components

1977 ◽  
Vol 30 (9) ◽  
pp. 1869 ◽  
Author(s):  
M Sheps ◽  
S Hacobian
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Approximation Schemes ◽  
Hydrazoic Acid ◽  
Gradient Tensor ◽  
Principal Axes ◽  
Set Up ◽  
Lcao Mo

It is possible to set up an electric field gradient criteria scheme as an aid in assessing the quality of theoretically derived electric field gradient (EFG) tensor components characterized by a non-zero asymmetry parameter. The analysis draws attention to the importance of checking that the theoretically predicted coordinate axes assignments of the principal axes system (PAS) for the EFG tensor components respectively agree with the assignments of the experimental PAS. An application of the PAS-assignment-criterion shows that some well known LCAO MO based EFG approximation schemes when tested on the hydrazoic acid molecule possess a serious limitation, as evidenced by their failure to obey this criterion.

The Temperature Dependence of 121,123Sb, 35Cl, 79,81Br and 127I NQR Spectra in Complexes Cs3Sb2X9 (X = Cl, Br, I)

2000 ◽  
Vol 55 (1-2) ◽  
pp. 134-138 ◽  
Author(s):  
L. A. Zemnukhova ◽  
S. I. Kuznetsov ◽  
G. A. Fedorishcheva ◽  
R. L. Davidovich
Keyword(s):  
Electric Field ◽  
Aqueous Solutions ◽  
Electric Field Gradient ◽  
Temperature Dependence ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Quadrupole Transition ◽  
Quadrupole Coupling ◽  
Coeffi Cients ◽  
Constant E

The 123,123Sb, 35Cl, 79,81Br and 127I NQR Spectra of the complexes Cs3Sb2X9 (X = Cl, Br, I), prepared from CsX and SbX3 aqueous solutions, were studied at 77-400 K. Analysis of the^ temperature coeffi-cients of the quadrupole transition frequency (v), quadrupole coupling constant (e2Qqzz) and asymme-try parameter of the electric field gradient (η) was carried out.

FT-NMR Detection of 45Sc, 49Ti and 93Nb in TiO2 Single Crystal

1998 ◽  
Vol 53 (6-7) ◽  
pp. 549-551
Author(s):  
K. Sato ◽  
S. Takeda ◽  
S. Fukuda ◽  
T. Minamisono ◽  
M. Tanigaki ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Stable Isotope ◽  
Single Crystal ◽  
Field Gradient ◽  
Quadrupole Moment ◽  
Electric Quadrupole ◽  
Quadrupole Coupling Constant ◽  
Electric Quadrupole Moment ◽  
Coupling Constant ◽  
Quadrupole Coupling

Abstract In order to determine the electric quadrupole moment of the short-lived β-emitter 41Sc from the quadrupole coupling constant in TiO2 , we measured the field gradient by detecting the Fourier-Transformed-NMR of stable isotope 45Sc doped in TiO2. Also, in order to study the electronic structure of impurities systematically, EFGs were measured for 45Sc, 49Ti and 93Nb in a TiO2 ingle single crystal.

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