A composite pulse sequence for the broadband excitation in overtone 14N NMR spectroscopy

In this Letter, a composite π/2 pulse sequence, 45 135, for the broadband excitation in overtone NMR spectroscopy of spin S=1 quadrupolar nuclei is proposed. The performances of single and composite π/2 pulses against resonance offset and rf field inhomogeneity are compared based on the results from 14N overtone experiments on a single crystal sample of N-acetyl-D,L-valine. The results reveal that the 45 135 composite π/2 pulse is less sensitive to the pulse imperfections and it will be useful in the design of multidimensional overtone NMR experiments.