Theoretical calculation of a composite pulse for H broadband excitation by average Hamiltonian theory.

Quadrupolar echo NMR spectroscopy of solids often requires RF pulse excitation that covers spectral widths exceeding 100 kHz. In a recent work we found out that a four pulse, composite pulse COM-II ( [Formula: see text] ), provided robust broadband excitation for deuterium quadrupolar echo spectroscopy. Moreover, when combined with an eight step phase cycle, spectral distortions arising from finite pulse widths were greatly supressed.

Revisiting NMR composite pulses for broadband (2)H excitation.

Quadrupolar echo NMR spectroscopy of static solids often requires RF excitation that covers spectral widths exceeding 100 kHz, which is difficult to obtain due to instrumental limitations. In this work we revisit four well-known composite pulses (COM-I, II, III and IV) for broadband excitation in deuterium quadrupolar echo spectroscopy. These composite pulses are combined with several phase cycling schemes that were previously shown to decrease finite pulse width distortions in deuterium solid-echo experiments performed with two single pulses.