scholarly journals Crystal Structure Refinement and Single Crystal 81Br Zeeman NQR Study of KHgBr3· H2O

1996 ◽  
Vol 51 (12) ◽  
pp. 1197-1202 ◽  
Author(s):  
Hiromitu Terao ◽  
Tsutomu Okuda ◽  
Sachiyo Uyama ◽  
Hisao Negita ◽  
Shi-qi Dou ◽  
...  
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Structure Refinement ◽  
Zeeman Effect ◽  
Coupling Constants ◽  
X Ray ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters ◽  
Good Agreement

Abstract Three 81Br NQR resonance lines of KHgBr3 ·H2O were detected between 77 K and room temperature. From the Zeeman effect measurement on a single crystal the nuclear quadrupole coupling constants (e2qQ/h) and the asymmetry parameters (ƞ) were obtained, which are 228.42 MHz and 0.005, 226.24 MHz and 0.005, and 108.76 MHz and 0.465 for e2qQ/h and ƞ at 295 K, respectively. Large deviations of the observed directions of electric field gradient tensors from the directions expected from previous X-ray results have been found. With the present X-ray redetermination, 81Br NQR and structure are in good agreement. The structure and bonding in the compound are discussed.

The C—CI Bonds in α -2,4,6-tris(trichIoromethyl)-1,3,5-trioxane, α -Parachloral, (Cl3CCHO)3. A 35Cl-NQR Single Crystal Study

1985 ◽  
Vol 40 (4) ◽  
pp. 324-334 ◽  
Author(s):  
Masao Hashimoto ◽  
Norbert Weiden ◽  
Alarich Weiss
Keyword(s):  
Single Crystal ◽  
Coupling Constants ◽  
X Ray Diffraction ◽  
X Ray ◽  
Principal Axes ◽  
Quadrupole Coupling ◽  
35Cl Nqr ◽  
Single Crystal Study ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

By single crystal 35C1-NQR Zeeman spectroscopy, the five independent 35Cl nuclear quadrupole coupling tensors in a-parachloral, (Cl3CCHO)3, have been studied at 24 ± 2 °C. The directions of the electric field gradient (EFG) tensor components have been determined. The principal axes Φ are within ± 0.8° parallel to the C-Cl bond directions found by X-ray diffraction. Very small asymmetry parameters in the range 0.002 ≦ η ≦ 0.046 are characteristic for the EFG tensors of chlorine atoms bound to carbon atoms in aliphatic systems. The five nuclear quadrupole coupling constants are in the range 76.752 ≦ e2qQh-1/MRz ≦ 78.155. The orientation of the principal axes Φxx and Φyy can be correlated to the molecular structure.

14N and 39K Nuclear Quadrupole Coupüng in KNO3

1990 ◽  
Vol 45 (3-4) ◽  
pp. 459-463 ◽  
Author(s):  
T. J. Bastow ◽  
S. N. Stuart
Keyword(s):  
Phase Transition ◽  
Nuclear Magnetic Resonance ◽  
Room Temperature ◽  
Potassium Nitrate ◽  
Nuclear Quadrupole Interaction ◽  
Coupling Constants ◽  
Disorder Phase Transition ◽  
Nuclear Quadrupole ◽  
T Values ◽  
Asymmetry Parameters

Abstract The nuclear quadrupole interaction tensors of 14N and 39K in potassium nitrate at room temperature have been determined from nuclear magnetic resonance (NMR) rotation studies of single crystals at 9.4 T. Values for the coupling constants and asymmetry parameters at 296 K are:14N: e2 qQ/h = 751 kHz, η = 0.022; 39K: e2 qQ/h = 1326kHz, η = 0.171. The temperature dependence, on approaching the order-disorder phase transition near 401 K, is linear.

Theory of Nuclear Quadrupole Interactions of 14N, 17O, and 35Cl Nuclei in p-Cl-Ph-CH-N=TEMPO

2002 ◽  
Vol 57 (6-7) ◽  
pp. 527-531
Author(s):  
Junho Jeong ◽  
Tina M. Briere ◽  
N. Sahoo ◽  
T. P. Das ◽  
S. Ohira ◽  
...  
Keyword(s):  
Muon Spin ◽  
Hyperfine Interactions ◽  
Rotation Frequency ◽  
Coupling Constants ◽  
Muon Spin Rotation ◽  
Hartree Fock ◽  
Nuclear Quadrupole Interactions ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

The nuclear quadrupole coupling constants and asymmetry parameters have been studied for the 35Cl, 17O, and 14N nuclei in the molecular ferromagnet 4-(p-chlorobenzylideneamino)-TEMPO (2,2,6,6-tetramethyl- piperidin-1-yloxyl) using elctronic stuctures obtained by the Hartree-Fock procedure for the bare system and systems with trapped muon and muonium. Trends in the sizes of the coupling constants and asymmetry parameters for the various nuclei have been studied, and possible physical explanations have been proposed. For the systems with trapped muon or muonium, very substantial influences of the muon and muonium on the coupling constants and asymmetry parameters for the nuclei close to the trapping sites have been observed. The coupling constants and asymmetry parameters are found to be very different for the various nuclei, for the two cases where muon is trapped near chlorine and muonium near oxygen, indicating that, if experimental data were available to compare with theory, one could make conclusions about which of these two centers is responsible for the observed muon spin rotation frequency associated with the muon magnetic hyperfine interactions in these two trapped systems

scholarly journals Hydrogen Bond Studies. 125. A Deuteron Magnetic Resonance Study of Strontium Formate Dihydrate, Sr(HCOO)2 · 2D2O

1977 ◽  
Vol 32 (9) ◽  
pp. 1025-1029 ◽  
Author(s):  
Bo Berglund ◽  
Jörgen Tegenfeldt
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Magnetic Resonance ◽  
Electric Field Gradient ◽  
Room Temperature ◽  
Coupling Constants ◽  
Water Molecules ◽  
Magnetic Resonance Study ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

AbstractA room temperature (25 °C) deuteron magnetic resonance (DMR) study of a single crystal of Sr (HCOO)2 · 2 D2O is reported. Signals from all water molecules in the unit cell have been detected, and all four independent electric field gradient (EFG) tensors at the water deuterons have been determined from 409 quadrupole splittings. All spectra were recorded by rotating the crystal about one arbitrarily selected axis. The following quadrupole coupling constants and asymmetry parameters for the deuterons were obtained: 213.5(4), 189.3(4), 195.7(4) and 200.7(5) kHz and 0.117(3), 0.110(4), 0.116(4) and 0.098(3). The directions of the eigenvalues are qualitatively consistent with the crystal structure refined by Galigné 1; the result is in disagreement, however, with the earlier DMR study of Sr (DCOO)2 · 2 D2O (Reference 2).

NQR Studies of the Structure of Glasses and Crystalline Compounds

1992 ◽  
Vol 47 (1-2) ◽  
pp. 30-38 ◽  
Author(s):  
P. J. Bray ◽  
DongHoon Lee ◽  
De Gen Mao ◽  
G. L. Petersen ◽  
S. A. Feller ◽  
...  
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Borate Glasses ◽  
Low Frequencies ◽  
Structure Of Glasses ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

AbstractPure nuclear quadrupole resonance (NQR) spectroscopy at low frequencies (down to 275 kHz) has been used to investigate a number of borate, aluminate, and vanadate crystalline compounds and borate glasses. The values of the quadrupole coupling constants (Qcc) and asymmetry parameters (η) are obtained with error limits that are one or two orders of magnitude less than those for values obtained from NMR spectra. New sites, not resolved in NMR spectra, have been detected for boron in borate glasses.

High Pressure NQR Study of the Phase Transition in Anilinium Iodide

1986 ◽  
Vol 41 (1-2) ◽  
pp. 290-293
Author(s):  
Mariusz Maćkowiak ◽  
Maria Zdanowska-Fra̧zek ◽  
Piotr Kozioł ◽  
Jan Stankowski ◽  
Alarich Weiss
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Transition Temperature ◽  
Hydrogen Bonds ◽  
Transition Point ◽  
Pressure Coefficient ◽  
Coupling Constants ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

The 127I NQR frequency in anilinium iodide C6H5NH3⊕I⊖ was studied at pressures up to 300 MPa and within the temperature range 77 K - 290 K. With increasing pressure the order-disorder transition point Tc is shifted to higher temperatures. The pressure coefficient of the phase transition temperature amounts to dTc/dp = 4.2 x 10-2 deg MPa-1. The pressure coefficient of the NQR frequency is negative. In addition, the 12'I nuclear quadrupole coupling constants and the respective asymmetry parameters η were evaluated as a function of pressure. The results confirm the close connection between the mechanism of the phase transition and the dynamics of the N - H⊕ ...I⊖ hydrogen bonds.

Preliminary Results of a 20 K X-Ray Study of Citrinin

1993 ◽  
Vol 48 (1-2) ◽  
pp. 99-104 ◽  
Author(s):  
R. Destro ◽  
F. Merati
Keyword(s):  
Dipole Moment ◽  
Hydrogen Bonds ◽  
Charge Density ◽  
Topological Analysis ◽  
Coupling Constants ◽  
Molecular Dipole ◽  
X Ray ◽  
A Value ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

Abstract A total of about 37 000 diffracted intensities has been measured at 20 K for a spherical single crystal of citrinin. Using a multipole formalism to interpret the X-ray data, maps of the charge density and of its Laplacian, as well as for the electrostatic potential have been derived. A value of 7(2) D has been obtained for the magnitude of the molecular dipole moment. A study of the electric field gradient (EFG) at the nuclei has yielded the atomic quadrupole coupling constants (QCC) and asymmetry parameters (η). A topological analysis of the charge density has been performed to characterize the intramolecular covalent and hydrogen bonds.

(CH3)3CCOOSbCl4: Structure Determination by Zeeman Perturbed NQR

1986 ◽  
Vol 41 (1-2) ◽  
pp. 129-133 ◽  
Author(s):  
Maria L. S. Garcia ◽  
Edwin A. C. Lucken
Keyword(s):  
Molecular Structure ◽  
Magnetic Field ◽  
Crystal Structure ◽  
Single Crystal ◽  
Structure Determination ◽  
Organic Ligand ◽  
Coupling Constants ◽  
Zero Field ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

A single crystal of tetrachloro(0,0-pivaloylato)antimony(V) has been studied at 77 K, byZeeman perturbed 35Cl NQR, using a FT-NQR pulsed spectrometer. The four lines at zero-field, ν1 = 27.6468, ν2= 27.3070, ν3= 25.7341 and ν4= 25.3438 MHz yield eight EFG tensors in themagnetic field, related by a twofold symmetry element in the crystal. The correspondingasymmetry parameters are η1, = 0.134, η2 = 0.13, η3= 0.07, and η4 = 0.09. The molecular structurededuced from the relative orientations of the principal Z-axes of the EFG tensors confirms that thehigher quadrupole coupling constants are associated with the chlorine atoms in equatorial positions,relative to the plane of the organic ligand, as predicted from NQR powder studies. It is concludedthat the crystal structure is monoclinic with two (class m or 2) or four (class 2/m) moleculesper unit cell. The molecular packing is such that the planes formed by equatorial or axial chlorineatoms are approximately at right angles to their symmetry related images.

Experimental Study of Nuclear Electric Quadrupole Splittings of 59Co in Co(NH3)6Cl3

1974 ◽  
Vol 52 (15) ◽  
pp. 1398-1404 ◽  
Author(s):  
E. C. Reynhardt
Keyword(s):  
Experimental Study ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Electric Field Gradient ◽  
Room Temperature ◽  
Electric Quadrupole ◽  
Coupling Constants ◽  
Principal Axes ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

The nuclear magnetic resonance of 59Co in a single crystal of Co(NH3)6Cl3 has been investigated at room temperature at 15 kG. Observed quadrupolar perturbations have been analyzed by the method of Volkoff for three orthogonal planes to yield five electric field gradient tensors. The cobalt sites associated with these tensors are nonequivalent. The quadrupole coupling constants and asymmetry parameters vary from 1.0 to 17.2 MHz and 0.10 to 0.57 respectively. One of the principal axes of each tensor is found to coincide with the crystallographic b axis of the monoclinic unit cell.

NUCLEAR MAGNETIC RESONANCE SPECTRUM OF B11 IN KERNITE

1955 ◽  
Vol 33 (5) ◽  
pp. 156-175 ◽  
Author(s):  
H. H. Waterman ◽  
G. M. Volkoff
Keyword(s):  
Magnetic Field ◽  
Coupling Constants ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Principal Axes ◽  
Quadrupole Coupling ◽  
Radio Frequency Spectrum ◽  
Asymmetry Parameters ◽  
Crystallographic Axes ◽  
The Magnetic Field

The radio-frequency spectrum of B11 in a single crystal of Na2B4O7∙4H2O (kernite) is examined experimentally as the monoclinic crystal is rotated in an external magnetic field of 7060 gauss in turn about each of three axes (b, c crystallographic axes, and a third perpendicular direction) held normal to the magnetic field. A maximum of 21 lines (some of which show small additional splitting) is observed, which reduces to 11 when the b symmetry axis is perpendicular or parallel to the magnetic field. The results are interpreted in terms of four essentially non-equivalent B11 sites in kernite characterized respectively by quadrupole coupling constants [Formula: see text], 0.588 ± 0.003, 2.563 ± 0.007, 2.567 ± 0.010 Mc./sec, and asymmetry parameters 77 [Formula: see text], 0.60 ± 0.02, 0.163 ± 0.010, 0.116 ± 0.010. The orientations of the principal axes of the four [Formula: see text] tensors are also determined. These observations on boron are consistent with previous X-ray results, but preliminary observations on Na23 in kernite contradict previous X-ray position assignments.

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