Relaxation of Spin 1/2 in the Scalar Coupled Spin System AMX with Quadrupolar Nuclei in the Presence of Cross-correlation Effects

2004 ◽  
Vol 59 (4-5) ◽  
pp. 217-4
Author(s):  
G. S. Kupriyanova
Keyword(s):  
Spin System ◽  
Cross Correlation ◽  
Relaxation Times ◽  
Formal Theory ◽  
Quadrupolar Nuclei ◽  
Transverse Relaxation ◽  
Selective Determination ◽  
Product Operator ◽  
Dynamic Frequency

We present the formal theory of the nuclear magnetic relaxation of spin ½ A in a scalar coupled spin system AMX with quadrupolar nuclei of spin 1 (M, X) considering cross-correlation relaxation based on second order time-dependent perturbation theory and the product operator formalism. The expressions for longitudinal and transverse relaxation times and dynamic frequency shifts of each component of the spectral pattern are derived. Several experimental schemes for the selective determination of the cross-correlation rate between different spin orders are proposed.

A Selective Determination of the Proton Nuclear Relaxation Times of the Alkaloid Vindoline: An Extension via Fourier Transform Measurements

1974 ◽  
Vol 52 (5) ◽  
pp. 829-832 ◽  
Author(s):  
L. D. Hall ◽  
Caroline M. Preston
Keyword(s):  
Fourier Transform ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Nuclear Relaxation ◽  
Transform Method ◽  
Fourier Transform Method ◽  
Selective Determination ◽  
Spin Lattice

A Fourier Transform method has been used to measure the spin–lattice relaxation times of essentially all the protons of the alkaloid, vindoline. It is shown that even for a molecule of this size substantial and potentially useful differences exist in the experimental relaxation times which reflect the degree of crowding of each proton by other protons.

Spin-echo methods for the determination of 31P transverse relaxation times of the ATP NMR signals in vivo

1994 ◽  
Vol 12 (1) ◽  
pp. 121-129 ◽  
Author(s):  
Klaus Straubinger ◽  
Wulf-Ingo Jung ◽  
Michael Bunse ◽  
Otto Lutz ◽  
Klaus Küper ◽  
...  
Keyword(s):  
Spin Echo ◽  
Relaxation Times ◽  
Transverse Relaxation ◽  
Nmr Signals

A pitfall associated with determination of transverse relaxation times of the31P NMR signals of ATP using the Hahn spin-echo

1993 ◽  
Vol 30 (1) ◽  
pp. 138-141 ◽  
Author(s):  
Wulf-Ingo Jung ◽  
Klaus Straubinger ◽  
Michael Bunse ◽  
Stefan Widmaier ◽  
Fritz Schick ◽  
...  
Keyword(s):  
Spin Echo ◽  
Relaxation Times ◽  
Transverse Relaxation ◽  
Nmr Signals

Tone-Bursting of Quadrupolar Nuclei. Determination of the Spin–Lattice Relaxation Times in Ferroelectric Lithium Tantalate and Lithium Niobate

1972 ◽  
Vol 50 (10) ◽  
pp. 966-975 ◽  
Author(s):  
J. D. Stroud ◽  
R. B. Creel ◽  
S. L. Segel ◽  
R. J. Schoenberger
Keyword(s):  
Lithium Niobate ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Electric Quadrupole ◽  
Lithium Tantalate ◽  
Spin Lattice Relaxation ◽  
Quadrupolar Nuclei ◽  
Quadrupole Relaxation ◽  
Spin Lattice

The technique of "tone-bursting" for the determination of spin–lattice relaxation times has been extended to quadrupolar nuclei and applied to two ferroelectric crystals: lithium tantalate and lithium niobate. The approach has been to analytically follow the populations of the Zeeman quadrupole levels through each passage through resonance and determine the effective T1 from the decrease in magnetization. The analytic results agree with the computer results obtained by Creel and Barnes. The results also agree with the conclusion of Walstedt that the relaxation rate is enhanced by a factor of [Formula: see text] when only the central resonance is being irradiated in a quadrupolar split pattern.Application of the technique to 7LiTaO3 yields a value of 3.0 ± 1.0 s for the effective T1, dominated by magnetic dipole relaxation. For 7LiNbO3, the effective T1 is 33 ± 5.0 s for the central transition and the relaxation mechanism is predominantly electric quadrupole relaxation.

A Selective Determination of the Proton Nuclear Relaxation Times of the Alkaloid Vindoline

1972 ◽  
Vol 50 (4) ◽  
pp. 497-503 ◽  
Author(s):  
R. Burton ◽  
C. W. M. Grant ◽  
L. D. Hall
Keyword(s):  
Relaxation Time ◽  
Spin Relaxation ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Nuclear Relaxation ◽  
Methyl Group ◽  
Selective Determination ◽  
Spin Lattice

An audiofrequency-pulse n.m.r. spectrometer has been used to measure the nuclear relaxation times of individual protons of the alkaloid, vindoline. For this substance in deuterochloroform solution the spin–lattice relaxation times (T1) vary between 1.15 and 1.50 s and the spin–spin relaxation times (T2) are between 0.90 and 1.40 s. The N-methyl group has the shortest relaxation time of those resonances which were measured. A discussion of the apparatus and methodology is given.

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