Nuclear Quadrupole Resonance of Antimony in Ln3Sb5O12 Crystals

1994 ◽  
Vol 49 (6) ◽  
pp. 687-689 ◽  
Author(s):  
A. M. Raevsky ◽  
A. G. Gukalova ◽  
G. K. Semin
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Compression Effect ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters ◽  
Lanthanide Compression

Abstract Complete 121,123Sb NQR spectra of crystalline rate earth antimonites Ln3Sb5O12 (Ln = La, Nd, Er, Lu) were recorded at 77 K. The quadrupole coupling constants and asymmetry parameters of the electric field gradient were measured. A “lanthanide compression” effect on the antimony NQR was observed. Using relations found for the antimonites under study, the Sb spectral parameters of other lanthanide compounds can be predicted.

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.

The chemical interpretation and the temperature dependence of the 14N nuclear quadrupole resonance of aniline and several derivatives

1968 ◽  
Vol 46 (22) ◽  
pp. 3595-3604 ◽  
Author(s):  
C. T. Yim ◽  
M. A. Whitehead ◽  
Donald H. Lo
Keyword(s):  
Temperature Dependence ◽  
Nuclear Quadrupole Resonance ◽  
Coupling Constants ◽  
Temperature Range ◽  
Resonance Frequencies ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters ◽  
Phenylene Diamine

The 14N nuclear quadrupole resonance frequencies of aniline, o- and p-phenylene diamine, and p-chloro-, p-bromo-, and p-iodo-aniline were measured with a super-regenerative oscillator over a temperature range from 77 to 292 °K. The temperature dependence is analyzed. The chemical interpretation of the quadrupole coupling constants and asymmetry parameters is described.

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).

14N Quadrupole Cross-Relaxation Spectroscopy of a Compound of Pharmacological Interest

1986 ◽  
Vol 41 (1-2) ◽  
pp. 195-199 ◽  
Author(s):  
P. M. G. Bavin ◽  
D. Stephenson ◽  
J. A. S. Smith
Keyword(s):  
Relaxation Times ◽  
Cross Relaxation ◽  
Coupling Constants ◽  
Relaxation Techniques ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Pharmacological Interest ◽  
Polymorphic Forms ◽  
Spectral Intensities ◽  
Asymmetry Parameters

Cross-relaxation spectroscopy has been used to record the 14N quadrupole resonance spectrum of two of the polymorphic forms of the pharmacologically-important compound: 2-4-(5-Bromo- 3-methylpyrid-2-yl)butylammo-5-(6-methylpyrid-3-yl)methyl-pyrimidin-4-one.Three 14N frequencies for four of the non-equivalent nitrogen sites within the molecule have been identified by combined irradiation and cross-relaxation techniques and quadrupole coupling constants and asymmetry parameters deduced therefrom; the absence of 14N (and 79Br) signals from the bromine-substituted pyridine ring suggests that this part of the molecule is disordered in the crystal. The spectral intensities have been used to derive approximate values for the 14N and 1H relaxation times, which show clear differences between the two polymorphs.

Ab initio Calculations of the Nuclear Quadrupole Coupling Constants of BHn = 2,4X+ (X = NH3, PH3, H2O, H2S)

2005 ◽  
Vol 60 (1-2) ◽  
pp. 37-40
Author(s):  
Tayyebe Partovi ◽  
Marjan A. Rafieea
Keyword(s):  
Electronic Structure ◽  
Electric Field Gradient ◽  
Coupling Constants ◽  
The Other ◽  
Quadrupolar Nuclei ◽  
Donor Atom ◽  
Acid Base ◽  
Donor And Acceptor ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

The electronic structure and strength of acid-base bonding in the protonated boron-Lewis complexes BHn=2,4X+ (X = NH3, PH3, H2O, H2S) and their neutral parents were studied. The results showed that in the H2BX+ monocations the electron releasing from the donor atom in X to BH3 is significant and more complete than in the other studied complexes. Therefore the bonding between the donor and acceptor in H2BX+ is strongest. To obtain these data, the electric field gradient (EFG) at the quadrupolar nuclei in each complex was calculated. The EFG’s of the boron atom and other quadrupolar nuclei were calculated by the Gaussian 98 program, using the MP2/6-31G** method.

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.

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

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