Efficient 5QMAS NMR of spin-5/2 nuclei: use of fast amplitude-modulated radio-frequency pulses and cogwheel phase cycling


Bräuniger, Thomas, Pike, Kevin J., Harris, Robin K. and Madhu, P.K. (2003) Efficient 5QMAS NMR of spin-5/2 nuclei: use of fast amplitude-modulated radio-frequency pulses and cogwheel phase cycling. Journal of Magnetic Resonance, 163, (1), 64-72. (doi:10.1016/S1090-7807(03)00124-1).

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Description/Abstract

We report here an efficient multiple-quantum magic-angle spinning (MQMAS) pulse sequence involving fast amplitude-modulated (FAM) radio-frequency pulses for excitation and conversion of five-quantum (5Q) coherences of spin-5/2 nuclei. The use of a FAM-I type pulse train for the conversion of 5Q into 1Q coherences proves to be easier to implement experimentally than the earlier suggested use of a FAM-II type sequence [J. Magn. Reson. 154 (2002) 280], while delivering at least equal signal enhancement. Results of numerical simulations and experimental 27Al 5QMAS spectra of aluminium acetylacetonate for different excitation and conversion schemes are compared to substantiate these claims. We also demonstrate the feasibility of acquiring 5QMAS spectra of spin-5/2 systems using cogwheel phase cycling [J. Magn. Reson. 155 (2002) 300] to select the desired coherence pathways. A cogwheel phase cycle of only 57 steps is shown to be as effective as the minimum conventional nested 77-step phase cycle.

Item Type: Article
ISSNs: 1090-7807 (print)
Related URLs:
Keywords: solid-state nmr, 5qmas, fam, sensitivity enhancement, cogwheel phase cycling, aluminium-27, quantum mas nmr, angle-spinning nmr, double frequency sweeps, quadrupolar nuclei, coherence-transfer, i=3/2 nuclei, mqmas nmr, signalenhancement, magnetic-resonance, triple
Subjects: Q Science > QD Chemistry
Q Science > QC Physics
Divisions: University Structure - Pre August 2011 > School of Chemistry
Item ID: 19913
Date Deposited: 23 Feb 2006
Last Modified: 02 Mar 2012 12:45
Contributors: Bräuniger, Thomas (Author)
Pike, Kevin J. (Author)
Harris, Robin K. (Author)
Madhu, P.K. (Author)
Date: 2003
Status: Published
URI: http://eprints.soton.ac.uk/id/eprint/19913

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