NMR studies of clustering in solids

We present a time-resolved multiple-quantum NMR experiment which allows us to determine the spatial distribution of atoms in materials lacking long-range order; in particular, we study the size and extent of atomic clustering in these materials.Multiple quantum NMR is sensitive to the distribution of spins in a solid.At the two extremes, uniformly distributed spins absorb rf quanta continuously whereas clustered groups of N spins can absorb only up to N quanta.Model experiments are demonstrated on the hydrogen distribution in selectively deuterated organic solids and in hydrogenated amorphous silicon.