Relaxation during spin-lock spin-echo pulse sequence in N14 nuclear quadrupole resonance

2008 ◽  
Vol 129 (21) ◽  
pp. 214504 ◽  
Author(s):  
Alan Gregorovič ◽  
Tomaž Apih
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Pulse Sequence ◽  
Spin Echo ◽  
Spin Lock ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Echo Pulse

Two-dimensional Nutation Echo Nuclear Quadrupole Resonance Spectroscopy

1990 ◽  
Vol 45 (3-4) ◽  
pp. 575-580 ◽  
Author(s):  
Gerard S. Harbison ◽  
Andris Slokenbergs
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Pulse Sequence ◽  
Resonance Spectroscopy ◽  
Zero Field ◽  
Two Dimensional ◽  
Quadrupolar Nucleus ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
The Asymmetry ◽  
Asymmetry Parameters

Abstract We discuss two new two-dimensional nuclear quadrupole resonance experiments, both based on the principle of nutation spectroscopy, which can be used to determine the asymmetry parameter, and thus the full quadrupolar tensor, of spin-3/2 nuclei at zero applied magnetic field. The first experiment is a simple nutation pulse sequence in which the first time period (t1) is the duration of the radiofrequency exciting pulse; and the second (t2) is the normal free-precession of a quadrupolar nucleus at zero-field. After double Fourier-transformation, the result is a 2 D spectrum in which the first frequency dimension is the nutation spectrum for the quadrupolar nucleus at zero-field. For polycrystalline samples this sequence generates powder lineshapes; the position of the singularities, in these lineshapes can be used to determine the asymmetry parameters η in a very straightforward manner, η has previously only been obtainable using Zeeman perturbed NQR methods. The second sequence is the same nutation experiment with a spin-echo pulse added. The virtue of this refocussing pulse is that it allows acquisition of nutation spectra from samples with arbitrary inhomogeneous linewidth; thus, asymmetry parameters can be determined even where the quadrupolar resonance is wider than the bandwidth of the spectrometer. Experimental examples of 35Cl, 81Br and 63Cu nutation and nutation-echo spectra are presented.

Exploiting Spin Echo Decay in the Detection of Nuclear Quadrupole Resonance Signals

2007 ◽  
Vol 45 (4) ◽  
pp. 925-933 ◽  
Author(s):  
Samuel D. Somasundaram ◽  
Andreas Jakobsson ◽  
John A. S. Smith ◽  
Kaspar Althoefer
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Spin Echo ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

scholarly journals Low Frequency Nuclear Quadrupole Resonance with SQUID Amplifiers

1994 ◽  
Vol 49 (1-2) ◽  
pp. 5-13 ◽  
Author(s):  
John Clarke
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Quantum Interference ◽  
Spin Echo ◽  
Relaxation Times ◽  
Noise Temperature ◽  
Low Frequency ◽  
Input Circuit ◽  
Transverse Relaxation ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Abstract The dc SQUID (Superconducting QUantum Interference Device) can be configured as an ampli­fier of spin-echos with a noise temperature of approximately 10 mK (f/1 M Hz) at an operating temperature of 1.5 K. A Fourier transform spectrometer based on a SQUID with a superconducting input circuit and operated in a flux-locked loop is used to obtain nuclear quadrupole resonance (NQR) spectra in a broadband m ode over the bandwith 0 -1 M Hz. Spin-echo spectra of 14N in NH4ClO4 reveal sharp NQR resonances, obtained simultaneously, at 17.4, 38.8 and 56.2 kHz. At 1.5 K, the measured longitudinal and transverse relaxation times T1 and T2 for the 38.8 kHz transition are 63 ± 3 ms and 22±2 ms, respectively.

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