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

Abstract

A first observation of the broad-range DRIFT spectra of carbon dioxide adsorbed on NaX zeolite allowed detection of the ν₂ CO₂ bending frequency of 619–625 cm^-1 and the ν₁ 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 ν₃ 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.