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.

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.

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

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.

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