Broadband, Narrowband, and Passband Composite Pulses for Use in Advanced NMR Experiments

Abstract

New composite pulses are derived and presented in a simple form where the overall flip angle remains a variable. Thus, composite pulses of overall flip angle 45°, 90°, 135°, 180°, or, for example, 54.7°, can be written down in a matter of seconds. Composite pulses that, at exact resonance, exhibit either broadband, narrowband, or passband behavior with respect to the strength of the radiofrequency field are demonstrated. The performance of all these composite pulses remains satisfactory over a range of normalized resonance offsets typical of 1H NMR spectroscopy. The most significant feature of the new composite pulses presented in this paper, however, is that they can be used to replace a simple pulse at any point in an advanced NMR experiment without further modification of the pulse sequence. © 1994 Academic Press. All rights reserved.