VIBRATIONAL-SPECTRA AND MOLECULAR-DYNAMICS STUDY OF THE CALCINED (NA+, K+) EMT HEXAGONAL FORMS OF FAUJASITIC ZEOLITES

The Raman scattering and infrared absorption spectra of dehydrated bar e NaEMT and KEMT zeolites were recorded in the mid- and low-frequency region. Molecular dynamics calculations based on a simplified general valence force field, the cation framework and cation-cation interactio ns reproduced the main structural and dynamic properties of the Na20EM T and K20EMT zeolites. The flexibility of the inner void space was stu died by considering the diameter and area of the windows connecting tw o adjacent medium or large cages. (C) 1997 Elsevier Science B.V.