Efficient 5QMAS NMR of spin-5/2 nuclei: use of fast amplitude-modulated radio-frequency pulses and cogwheel phase cycling
UNSPECIFIED (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). pp. 64-72. ISSN 1090-7807Full text not available from this repository.
Official URL: http://dx.doi.org/10.1016/S1090-7807(03)00124-1
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 IQ 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 Al-27 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. (C) 2003 Elsevier Science (USA). All rights reserved.
|Item Type:||Journal Article|
|Subjects:||Q Science > QD Chemistry
Q Science > QC Physics
|Journal or Publication Title:||JOURNAL OF MAGNETIC RESONANCE|
|Publisher:||ACADEMIC PRESS INC ELSEVIER SCIENCE|
|Number of Pages:||9|
|Page Range:||pp. 64-72|
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