Infrared spectroscopic study of the interaction of cations in zeolites with simple molecular probes. Part 3.—Adsorption and polarization of methane and ethane on cationic forms of high-silica zeolites

Adsorption of methane and ethane as molecular probes on cationic forms of high-silica zeolites has been investigated by diffuse reflectance infrared spectroscopy. In addition to physically adsorbed species of the alkanes, molecules perturbed via an interaction with the cations were observed. Such a polarization results in a low-frequency shift of the antisymmetric stretching vibrations of methane molecules. A linear correlation was found between the extent of CH4 polarization and the electrostatic field of the cation.