Powder Zeeman NQR Study on 123Sb in Sb(C6H5)3

2002 ◽  
Vol 57 (6-7) ◽  
pp. 304-306
Author(s):  
O. Ege ◽  
S. Maekawa ◽  
H. Negita
Keyword(s):  
Computer Simulation ◽  
Line Shape ◽  
Asymmetry Parameter ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Line Shapes ◽  
Quadrupole Coupling ◽  
Saddle Type ◽  
Lower Series ◽  
Good Agreement

Powder Zeeman NQR spectra of 123Sb in Sb(C6H5)3 were studied by means of a computer simulation and an experiment. The 123Sb nucleus has spin 7/2. There are two non-equivalent 123Sb atoms in the crystal of Sb(C6H5)3, so that there are two series of three transition lines (higher series: ν1h, ν2h, ν3h; lower series: ν11, ν21, v31). The powder Zeeman spectra for ν1h, based on the transition between the levels mI = ±1/2 and ±3/2, were observed at 77 K under the two conditions that i) the oscillation coil and the static magnetic coil were set coaxially and parallel, and ii) they were set perpendicular to each other. The powder line shapes for ν1h, which is the lowest line of the higher series due to 123Sb nuclei, were in good agreement with those from a computer simulation under the conditions i) and ii), showing that the asymmetry parameter of the field gradient is very small (η = 0). The line shape from i) exhibits two shoulders (saddle type), as it appeared for nuclear spin 5/2 and η = 0. The quadrupole coupling constant for 1h, calculated from the resonance frequency 47.820 MHz and the observed η, is 669.480 MHz at 77 K.

scholarly journals Two-Dimensional Nutation NQR Broad-Line Spectra in Oriented Samples

2006 ◽  
Vol 61 (9) ◽  
pp. 499-504 ◽  
Author(s):  
Nicolay Sinyavsky ◽  
Irina Korneva ◽  
Michał Ostafin ◽  
Bolesław Nogaj ◽  
Mariusz Maćkowiak
Keyword(s):  
Asymmetry Parameter ◽  
Disordered Systems ◽  
Quadrupole Coupling Constant ◽  
Two Dimensional ◽  
Coupling Constant ◽  
Nuclear Spins ◽  
Radio Frequency Field ◽  
Quadrupole Coupling ◽  
Oriented Samples ◽  
Constant E

The NQR nutation method to determine the electric field gradient asymmetry parameter η in systems, where the resonance line is so broad that the radio frequency field can excite only a portion of the nuclear spins, is presented. In this situation, the recently developed spectroscopic methods are not applicable. Two-dimensional nutation NQR spectra of oriented powders are calculated and used to determine η at particular frequencies along a broad NQR line. The proposed method is useful for single crystals, oriented powders, glasses, and disordered systems even for small values of the asymmetry parameter. Therefore it can be used to evaluate fluctuations in η and the quadrupole coupling constant e2qQ due to inhomogeneities. We demonstrate the application of this method to oriented chalcogenide semiconducting glasses.

scholarly journals High Resolution and Solid State NMR Investigations of Subvalent Gallium Compounds

1986 ◽  
Vol 41 (1-2) ◽  
pp. 315-318 ◽  
Author(s):  
Hubert Schmidbaur ◽  
Theodore Zafiropoulos ◽  
Wolfgang Bublak ◽  
Paul Burkert ◽  
Frank H. Köhler
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Gallium Atom ◽  
Line Shapes ◽  
Quadrupole Coupling ◽  
Structure Determinations ◽  
Constant E ◽  
Gallium Compounds

The 71Ga NMR spectra of Ga[GaX4] melts and of solutions in benzene and other hydrocarbons show discrete sharp GaI and broad GaIII resonances. In the light of recent structure determinations, the solution GaI signals must be attributed to bis(arene)Ga+ complexes in which the gallium atom is η6-bonded to the hydrocarbons. The low line widths and strong high field shifts are attributed to an almost spherical shielding of the metal nucleus by the 4 s2 electrons. Solid state 69Ga and 71Ga NMR spectra of Ga[GaCl4] crystalline powder show only Ga1 resonances. While the 71GaI line is rather narrow, the 69GaI line has a complex fine structure. Consistent with the crystal structure of Ga[GaCl4], the Ga1 ion is calculated to have a very low quadrupole coupling constant e2q Q/h = 1.7 ± 0.1 MHz and an asymmetry parameter η = 0.44. Experimental and simulated line shapes (using literature models) are in satisfactory agreement, implying that the 69Ga signal splitting is due to second order quadrupolar effects for the central m = + 1/2 ⇋ - 1/2 transition. The analogous splitting of the 71Ga NMR line is too small to be detected.

Pulsed nuclear magnetic resonance study of deuteron lineshapes in clathrate hydrates

1977 ◽  
Vol 55 (1) ◽  
pp. 78-81 ◽  
Author(s):  
John A. Ripmeester
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Asymmetry Parameter ◽  
Quadrupole Coupling Constant ◽  
Nuclear Magnetic Resonance Study ◽  
Coupling Constant ◽  
Magnetic Resonance Study ◽  
Guest Molecules ◽  
Quadrupole Coupling ◽  
Line Characteristic ◽  
Pulsed Nuclear Magnetic Resonance

D nmr lineshape information was obtained from the echo response following a pair of phase shifted pulses using a method first proposed by Clark. In this manner the D quadrupole coupling constant and asymmetry parameter for D2O in p-dioxane•17D2O were found to be 217 kHz and 0.10 at 63 K. The D nmr lineshape for ethylene oxide-d4•7H2O shows that at 17 K the guest molecules are held rigidly in their cages. At higher temperatures the doublet lineshape collapses to a broad structureless line characteristic of molecules for which the reorientational modes vary from cage to cage.

Hydrogen Bond Studies

1977 ◽  
Vol 32 (2) ◽  
pp. 134-139 ◽  
Author(s):  
Bo Berglund ◽  
Jörgen Tegenfeldt
Keyword(s):  
Asymmetry Parameter ◽  
Room Temperature ◽  
Sodium Perchlorate ◽  
Quadrupole Coupling Constant ◽  
Water Molecules ◽  
Coupling Constant ◽  
Nmr Spectrum ◽  
Quadrupole Coupling ◽  
Constant E ◽  
The Difference

The quadrupole splittings in the deuterium NMR spectrum from single crystals of deuterated sodium Perchlorate monohydrate, NaClO4-D2O, have been measured at 25 °C and - 55 °C. At room temperature, the 180° flip frequency of the D2O molecules is large compared to the difference between the splittings for the two deuterons. The average quadrupole coupling constant (e2 q Q/h) and asymmetry parameter η are 134.1(4) kHz and 0.621(5), respectively. At -55 °C, the electric field gradient tensors for each of the two deuterons were observed corresponding to slowly flipping water molecules, and e2 qQ/h and η for the two deuterons are 231.5(6) and 226.7(6) kHz and 0.196(4) and 0.195(5), respectively. The results indicate that the hydrogen positions in NaClO4-H2O are dynamically disordered

79,81Br and 133Cs Nuclei Quadrupole Interactions and Phase Transitions in Crystalline Caesium Perbromate

1990 ◽  
Vol 45 (7) ◽  
pp. 1005-1009 ◽  
Author(s):  
V. P. Tarasov ◽  
V. I. Privalov ◽  
Yu. A. Buslaev ◽  
U. Eichhoff
Keyword(s):  
Quadrupole Coupling Constant ◽  
Lattice Parameter ◽  
Coupling Constant ◽  
Linear Region ◽  
Line Shapes ◽  
Quadrupole Interactions ◽  
Quadrupole Coupling ◽  
Orientational Phase Transition ◽  
Spectral Simulations ◽  
Increasing Temperature

NMR experiments in solid caesium perbromate have recently been performed at magnetic fields of 1.88 T and 7.04 T together with spectral simulations for 79Br, 81Br and 133Cs in solid caesium perbromate. The line shapes are dominated by quadrupole effects. For bromine the quadrupole asymmetry parameter [η] is observed to be zero at all temperatures while the quadrupole coupling constant (CQ) as a function of temperature shows two approximately linear regions on either side of a non-linear region between 200 K and 260 K where an extended orientational phase transition occurs. 133Cs shows an increase of CQ and a decrease of η with increasing temperature. This behaviour may be associated with an anisotropic change of the “a” lattice parameter.

EPR Study of Mn2+ in Hg(ClO4)2 · 6H2O Single Crystals

1980 ◽  
Vol 35 (12) ◽  
pp. 1304-1307 ◽  
Author(s):  
Viraal Kuraar Jain
Keyword(s):  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
Hyperfine Transitions ◽  
Axial Part ◽  
X Band ◽  
Quadrupole Coupling ◽  
Electron Paramagnetic ◽  
Good Agreement

Abstract The electron paramagnetic resonance of Mn2+ in Hg(ClO4)2 · 6H2O has been studied at X-band at 298 K and 77 K. Mn2+ is found to substitute Hg 2+ . The spectra have been analysed using the spin-Hamiltonian appropriate for trigonal symmetry. From the unequal separations between the Δm = ± 1 doublets in M = + 1/2 → - 1/2 transitions, the value of the axial part of the quadrupole coupling constant is determined. The observed doublet separations of forbidden hyperfine transitions in M = + 1/2 → - 1/2 are in good agreement with those cal-culated.

Die Temperaturabhängigkeit der Kernquadrupolkopplungskonstante von Na23 in Natriumnitrit, NaNO2

1962 ◽  
Vol 17 (9) ◽  
pp. 794-798 ◽  
Author(s):  
Alarich Weiss ◽  
D. Biedenkapp
Keyword(s):  
Asymmetry Parameter ◽  
Transition Point ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Point Charge Model ◽  
Nuclear Quadrupole Coupling Constant ◽  
Charge Model ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Increasing Temperature

The nuclear quadrupole coupling constant of Na23 in sodium nitrite. NaNO2. has been investigated between 18 °C and 215 °C. Below the transition temperature (163 ± 2)°C the asymmetry parameter η= (φxx — φyy)/φzz decreases with increasing temperature and goes to zero at the transition point. Above 163 °C η is negative and | η | increases with temperature. This temperature dependence of the nuclear quadrupole coupling cannot be explained adequately by the point charge model together with the assumption of the free rotation of the NO2-group above the transition point.

Temperature Dependence of 14N NQR and Phase Transitions in KNO2 Powder

1996 ◽  
Vol 51 (5-6) ◽  
pp. 769-772 ◽  
Author(s):  
Hae Jin Kim ◽  
Kee Tae Han ◽  
Sung Ho Choh
Keyword(s):  
Phase Transitions ◽  
Temperature Dependence ◽  
Asymmetry Parameter ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Nuclear Quadrupole Coupling Constant ◽  
Quadrupole Coupling ◽  
Two Temperatures ◽  
Nuclear Quadrupole

Abstract The temperature dependence of 14N NQR, measured at 77 to 300 K, is in better agreement with the model proposed by Blinc et al. than the Bayer theory. The nuclear quadrupole coupling constant and asymmetry parameter show a discontinuity at about 160 K and 230 K, respectively. The linewidths are broadened at these temperatures up to 22 kHz and 18 kHz, respectively. These results indicate that KNO2 undergoes phase transitions at these two temperatures.

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