MIRROR-CP: A proton-only experiment for the measurement of 13C spin diffusion

Spin-diffusion measurements are applied in many solid-state NMR experiments. They require the preparation of non-equilibrium polarization on one spin species (S spins) which is often done through polarization transfer from a second spin species (I-spin). Such experiments involve radio-frequency irradiation at the Larmor frequencies of both spins. Here, we describe a method to generate and detect S-spin (13C) difference polarization via the I spins (1H) without S-spin pulses. No coil tuned to the S-spin (13C) resonance frequency is needed. On the basis of such a transfer step, S-spin spin diffusion can be measured in a single-channel I-spin (1H) experiment.