First observation of the broad-range DRIFT spectra of carbon dioxide adsorbed on NaX zeolite

A first observation of the broad-range DRIFT spectra of carbon dioxide adsorbed on NaX zeolite allowed detection of the nu(2) CO2 bending frequency of 619-625 cm(-1) and the nu(1) symmetric stretching frequency of 1358 cm(-1) calculated from the combination modes of adsorbed carbon dioxide stretching and bending vibrations. The vibrational frequencies of adsorbed molecules as a whole relative to adsorption sites were also obtained from positions of satellites of the nu(3) asymmetric stretching band of adsorbed molecules. The observation of several sets of satellites definitely indicates the existence in the NaX zeolite of at least two types of CO2 adsorption sites.