Vibrational spectra of O-18-exchanged NaZSM-5 and HZSM-5

Our research shows that O-18 exchange in NaZSM-5 causes isotopic shifts of the Raman bands of the sample. Shifts of i.r. bands were also detected for framework vibrations and for hydroxyl vibrations as well as for the appropriate combination modes in the spectra of O-18-exchanged NaZSM-5 and HZSM-5. The largest shifts were found for the most intense i.r. band at about 1,100 cm(-1) and the shoulder at about 1,200 cm(-1) as well as for the strongest Raman band at 381 cm(-1) This result agrees with the calculations of the vibrational spectra of framework cluster models with O-18 and O-16 atoms.