Pure absorption-mode spectra using a modulated RF mixing period in MQMAS experiments.
Different approaches to obtain pure absorption-mode lineshapes in MQMAS experiments employing a train of 180 degrees phase-alternating pulses for the multiple-quantum to single-quantum mixing period are investigated. Four pulse sequences, which achieve this by using either the shifted-echo approach or the hypercomplex approach with symmetric coherence transfer pathways, are presented and their improved lineshape- and sensitivity-performance is experimentally demonstrated by (87)Rb MQMAS of RbNO(3). Compared to the original modulated-rf mixing sequence, sensitivity enhancements by factors up to 1.3 are obtained with the sequences described here.
Vosegaard
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T
CRMHT-CNRS, 1D avenue de la Recherche Scientifique, Orléans, Cedex 2, 45071, France.
Florian
P
P
Grandinetti
P J
PJ
Massiot
D
D
D009682:Magnetic Resonance Spectroscopy / Q000379:methods*