Characterization of germanium site distribution in zeolite ITQ-7 by photoluminescence

Zeolite ITQ-7 containing germanium emits luminescence upon excitation at th e wavelength of the absorption maxima; control experiments with amorphous G eO2 and all-silica zeolites indicate that the emission is attributable to G e atoms occupying framework positions; the emission decays on the nanosecon d time scale and it fits to variable proportions of three exponential kinet ics, this being compatible with the presence of three families of Ge atoms in the solid.