Measurement of J-couplings between chemically equivalent nuclei using off-resonance decoupling.

The method of measuring J-couplings between chemically equivalent nuclei in isotopically/magnetically non-equivalent environment, based on off-resonance decoupling, is described. The approach uses intensities, rather than frequencies of the spectral peaks and, therefore, the accuracy of measurement is not limited by spectral resolution.

Communication: Long-lived states of nuclear spins in solids.

We report an observation of extremely long-lived spin states in systems of dipolar-coupled nuclear spins in solids. The "suspended echo" experiment uses a simple stimulated echo pulse sequence and creates non-equilibrium states which live many orders of magnitude longer than the characteristic time of spin-spin dynamics T2. Large amounts of information can be encoded in such long-lived states and subsequently retrieved by an application of a single "reading" pulse.