Composite pulses for efficient excitation of half-integer quadrupolar nuclei in NMR of static and spinning solid samples

0009-2614/$ see front matter 2012 Elsevier B.V. A doi:10.1016/j.cplett.2012.01.058 Abbreviations: CT, central transition; ST, satel quantum coherence; TQC, triple-quantum coherence. ⇑ Corresponding author. E-mail address: [email protected] (D. Carne Composite pulses of the type ðspÞxð2spÞ xð3spÞx allow one to excite the central transition of nuclei with half-integer spin with enhanced efficiency compared to a simple ðs p Þx pulse. The method has been tested on solid samples containing sodium-23 (I = 3/2), aluminium-27 (I = 5/2) and scandium-45 (I = 7/2) under both static and magic-angle spinning conditions. Numerical simulations for I = 3/2 indicate that the enhancement is due to a more efficient conversion of Zeeman population differences associated with the satellite transitions to the central transition. 2012 Elsevier B.V. All rights reserved.