LOCAL-MODE ANALYSIS OF COMPLEX ZEOLITE VIBRATIONS - SODALITE

We have developed a systematic procedure to analyze vibrational motion s in complex molecules and solids with large unit cells. This procedur e, based on group theoretical arguments, has been used to analyze the normal modes of sodalite. We find that certain linear combination of n ormal modes are: strongly spatially localized on the secondary buildin g units (SBUs) of this zeolite. Further, some of these local motions a re combinations of weakly coupled normal modes. This analysis leads us to believe that many of the normal modes can indeed be uniquely assoc iated with the SBUs of sodalite.