1. Department of Materials Science, Zeolites Engineering Lab., IMRE-Fac. Physics, University of Havana, Havana 10400, Cuba, Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, U.K., Department Physics, Fac. Sciences, Higher Pedagogical Inst. EJV, Ciudad Libertad, Playa, Havana 19220, Cuba, Inst. Superior Ciencias y Tecnología Nucleares, Ave. Salvador Allende y Luaces, Havana 10600, Cuba, and Davy Faraday Research Laboratory, Royal Institution of Great...