¹²⁹Xe Magic-angle spinning spectra of xenon in zeolite NaA direct observation of mixed clusters of co-adsorbed species

We present the first demonstration that the individual ¹²⁹Xe resonances corresponding to Xe_n (n = 1-8) clusters inside the α-cages of zeolite NaA can be narrowed under magic-angle spinning (MAS). Under these high-resolution conditions we also observe upon addition of Kr the individual peaks corresponding to mixed clusters, Xe_nKr_m, inside the a-cages, which will allow the first direct determination of the distribution of co-adsorbates in a microporous solid. Under MAS the chemical shifts of the Xe_n clusters are shown to be highly sensitive to “disorder” in the zeolite and provides new, quantitative information about the presence of α-cages of several types.