Krishnan , VV and Kumar, Anil (1991) Dipolar cross-correlation effects in the nuclear overhauser experiments of weakly and strongly coupled spins. In: Journal of Magnetic Resonance (1969), 92 (2). pp. 293-311.
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The effect of dipolar cross correlation in 1H---1H nuclear Overhauser effect experiments is investigated by detailed calculation in an ABX spin system. It is found that in weakly coupled spin systems, the cross-correlation effects are limited to single-quantum transition probabilities and decrease in magnitude as ωτc increases. Strong coupling, however, mixes the states and the cross correlations affect the zero-quantum and double-quantum transition probabilities as well. The effect of cross correlation in steady-state and transient NOE experiments is studied as a function of strong coupling and ωτc. The results for steady-state NOE experiments are calculated analytically and those for transient NOE experiments are calculated numerically. The NOE values for the A and B spins have been calculated by assuming nonselective perturbation of all the transitions of the X spin. A significant effect of cross correlation is found in transient NOE experiments of weakly as well as strongly coupled spins when the multiplets are resolved. Cross correlation manifests itself largely as a multiplet effect in the transient NOE of weakly coupled spins for nonselective perturbation of all X transitions. This effect disappears for a measuring pulse of 90° or when the multiplets are not resolved. For steady-state experiments, the effect of cross correlation is analytically zero for weakly coupled spins and small for strongly coupled spins.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier science.|
|Keywords:||Magnetic-Relaxation;Multispin Systems;C-13 Relaxation;Effect Spectra;Nmr;Spectroscopy;Biomolecules;Conformation; Simulation;Proteins.|
|Department/Centre:||Division of Chemical Sciences > Sophisticated Instruments Facility
Division of Physical & Mathematical Sciences > Physics
|Date Deposited:||16 Nov 2010 10:42|
|Last Modified:||16 Nov 2010 10:42|
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