The influence of J-coupling on heteronuclear nonlinear (or multiple) spin echoes

Heteronuclear nonlinear spin echoes were investigated with respect to the i nfluence of indirect spin-spin coupling in a two-spin 1/2 system consisting of H-1 and C-13 spins. The heteronuclear nonlinear spin echo phenomenon is essentially based on the C-13 coherence evolution in the presence of the m odulated demagnetizing field originating from the H-1 magnetization. It is shown that the first nonlinear C-13 echo amplitude oscillates as a function of the modulation period of the demagnetizing field (or the pitch of the p roton magnetization helix). The Fourier transform reveals a doublet with a splitting equal to the heteronuclear spin-spin coupling constant J. (C) 200 1 Elsevier Science B.V. All rights reserved.