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

Heteronuclear nonlinear spin echoes were investigated with respect to the influence of indirect spin–spin coupling in a two-spin 1/2 system consisting of 1H and 13C spins. The heteronuclear nonlinear spin echo phenomenon is essentially based on the 13C coherence evolution in the presence of the modulated demagnetizing field originating from the 1H magnetization. It is shown that the first nonlinear 13C echo amplitude oscillates as a function of the modulation period of the demagnetizing field (or the pitch of the proton magnetization helix). The Fourier transform reveals a doublet with a splitting equal to the heteronuclear spin–spin coupling constant J.