Use of SPAM and FAM pulses in high-resolution MAS NMR spectroscopy of quadrupolar nuclei

Ball, T.J. and Wimperis, S. (2007) Use of SPAM and FAM pulses in high-resolution MAS NMR spectroscopy of quadrupolar nuclei. Journal of Magnetic Resonance, 187(2), pp. 343-351. (doi: 10.1016/j.jmr.2007.05.020)

Abstract

The merits of SPAM and FAM pulses for enhancing the conversion of triple- to single-quantum coherences in the two-dimensional MQMAS experiment are compared using ⁸⁷Rb (spin I = 3/2) and ²⁷Al (I = 5/2) NMR of crystalline and amorphous materials. Although SPAM pulses are more easily optimized, our experiments and simulations suggest that FAM pulses yield greater signal intensity in all cases. In conclusion, we argue that, as originally suggested, SPAM and FAM pulses are best implemented in phase-modulated whole-echo MQMAS experiments and that the use of SPAM pulses to record separate echo and antiecho data sets, which are then combined, generally yields lower signal-to-noise ratios.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Wimperis, Professor Stephen
• Authors: Ball, T.J., and Wimperis, S.
• Subjects: Q Science > QD Chemistry
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of Magnetic Resonance
• ISSN: 1090-7807
• ISSN (Online): 1096-0856
• Published Online: 09 June 2007