Extending the excitation sculpting concept for selective excitation

Nowadays, excitation sculpting is probably the most efficient way to achiev e selectivity in an NMR experiment, since it associates very clean frequenc y selection with "user-friendliness." In the present report, it is shown th at the excitation sculpting concept, originally based on a double pulse fie ld gradient echo acting on a selected transverse magnetization, can be exte nded through new experiments designed to act on longitudinal magnetization. This leads to outstanding performances, especially when the transverse rel axation rate is a limiting factor as, for example, in the case of biologica l macromolecules. Several new sequences are proposed, aiming at the selecti on of magnetization aligned either/both on a transverse axis or/and on the z-axis. Their potentialities are illustrated in light of different applicat ions including multiplet-selective excitation, band-selective excitation, a nd water suppression. (C) 2000 Academic Press.