Simultaneous acquisition and effective separation of intermolecular multiple-quantum signals of different orders

Xiaoqin Zhu, Song Chen, Zhong Chen, Shuhui Cai and Jianhui Zhong
Chemical Physics Letters
Volume 438, Issues 4-6, 20 April 2007, Pages 308-314

Abstract
A three-pulse sequence was designed to simultaneously acquire intermolecular multiple-quantum coherence (iMQC) signals of coherence order n = 2, 1, 0, −1, −2. Analytical expressions were derived from modified Bloch equations. Signal of a specific order was obtained by optimal combinations of data from different acquisition steps. This allows a time saving of 5/7 compared to the phase cycling designs targeted for individual coherence orders. The method also results in pure iMQC signal of all the above five orders which are insensitive to radio-frequency flip angle errors, in contrast to some previous methods. Theoretical predictions are supported by the experimental observations and numerically simulated results.