Measurement of heteronuclear dipolar couplings using a rotating frame solid-state NMR experiment

A new NMR experiment to measure heteronuclear dipolar couplings in the solid-state is proposed. In this technique, a spin-lock based on a multiple pulse sequence, BLEW, is used in both the radio frequency channels to suppress the chemical shift and homonuclear dipolar coupling interactions. The spin part of the zeroth-order average Hamiltonian is isotropic at on-resonance and renders the heteronuclear isotropic mixing leading to spin exchange via the local field (HIMSELF) for an in phase transfer of magnetization. The offset frequency dependence is compensated by a 180° pulse at the end of a BLEW sequence. Theoretical, simulated and experimental results demonstrating the performance of the HIMSELF technique are reported.