Bromine-81 and chlorine-35 NMR investigation of sodium, silver, halo-sodalite semiconductor supralattices Academic Article uri icon

abstract

  • Br-81 and Cl-35 NMR yields, respectively, bromide and chloride site-specific information pertinent to the structural and electronic properties of Na8-n-pAgnX2-p-sodalite, semiconductor cluster supralattices, where X = Br, Cl; 0 less-than-or-equal-to n less-than-or-equal-to 8; 0 less-than-or-equal-to p less-than-or-equal-to 2. The Br-81 and Cl-35 MAS chemical shifts and line shapes observed for encapsulated Na4X and Ag4X clusters within the sodalite cavities provide insight into the nature of the intracluster bonding (ionic-covalent character) and the extent of intercavity coupling. Substantial nuclear shielding is observed for encapsulated Ag4X clusters in sodalite materials with high loading of Ag4Br clusters, whereas no NMR signal is detected from silver-bromide clusters isolated within sodalite lattices. Spin-lattice and spin-spin relaxation measurements yield information on intracavity coupling and motion within the sodalite cages. The results enable one to explore the transition from isolated clusters to an expanded Ag4X supralattice, through the compositional and temperature dependence of the NMR spectra of the sodalite halide anions.

publication date

  • May 1, 2002