THE EFFECTS OF FREQUENCY-SELECTIVE RF PULSES ON J-COUPLED SPIN-1/2 SYSTEMS

The effects of solvent-suppression, sinc-Gauss, self-refocussed, and 2D selective RF pulses on J-coupled spin systems have been investigated by means of computer simulations. Depending on the pulse time, coupling constants, and chemical shifts, nonnegligible amounts of unwanted coherence may be generated, resulting in signal loss and deteriorated slice profiles. A time-inverted self-refocused frequency-selective pulse is useful for frequency-selective multiple-quantum generation and spectral editing. Volume-selective pulses with bandwidths in the order of the chemical-shift range may lead for the PRESS experiment to severe signal cancellation. The SADLOVE localization sequence does not have this effect. It is shown that except for multiple-pulse localization sequences, with RF bandwidths on the order of the chemical-shift range, the effects of J coupling can be neglected for in vivo use. (C) 1994 Academic Press, Inc.