PULSE CASCADES - SIMPLE DESCRIPTION OF THE FLIP ANGLE DEPENDENCE OF NMR-SPECTRA

A simple physical picture which correctly predicts the flip angle effect" in Fourier transform spectroscopy discussed by Ernst and co-workers is presented. The approach is based on populations alone and does not require knowledge of the density matrix formalism. Nonselective pulses are represented by a "cascade" of consecutive pulses which affect only certain sets of transitions at a time. It is shown that the relative timing of the pulses within the cascade is unimportant provided the intervals are all short with respect to nuclear precession rates and relaxation. © 1979."