MOLECULAR-DYNAMICS STUDY OF THE VIBRATIONAL-SPECTRA OF SILICEOUS ZEOLITES BUILT FROM SODALITE CAGES

A molecular dynamics computer simulation of sodalite cage containing siliceous zeolites (sodalite, zeolite A, and faujasite) as well as silicalite was carried out. Two force fields based on a simplified version of the Urey-Bradley force field were examined in the calculations. It is shown that both of them lead to the same structural characteristics but to different vibrational spectra for the zeolite frameworks. The calculated infrared and Raman spectra are compared with available experimental and theoretical data. The influence of different terms in the potential function and of the lattice symmetry as well as common trends in the calculated spectra are discussed.