CORRELATION SPECTROSCOPY WITH 2 SIMULTANEOUS SOFT PULSES (TSETSE)

An analysis is presented of a new correlation experiment where two sel f-focusing soft pulses are applied simultaneously to two coupled spins I and S. It is shown that for a certain pulse duration, antiphase dis persion-mode doublets are observed at both sites, although the corresp onding single-excitation experiment displays only in-phase absorption. At longer pulse durations appreciable amounts of multiple-quantum coh erence are created. Simulations of this behavior are presented in the form of magnetization trajectories during a pair of soft E-BURP-2 puls es, and these predictions are compared with experiments on heteronucle ar two-spin systems. The effect (called ''TSETSE'') shows promise as a one-dimensional correlation experiment and as a practical method of d etermining scalar coupling constants. An application to the determinat ion of long-range C-H couplings in brucine is reported. (C) 1995 Acade mic Press, Inc.